<SUBMISSION>
<ACCESSION-NUMBER>0000950005-03-000186
<TYPE>SC 13G/A
<PUBLIC-DOCUMENT-COUNT>1
<FILING-DATE>20030213
<GROUP-MEMBERS>ALAN W. CRITES ("CRITES")
<GROUP-MEMBERS>ARNOLD L. ORONSKY ("ORONSKY")
<GROUP-MEMBERS>GILBERT H. KLIMAN ("KLIMAN")
<GROUP-MEMBERS>HARVEY B. CASH ("CASH")
<GROUP-MEMBERS>INTERWEST INVESTORS VI, LP ("II VI")
<GROUP-MEMBERS>INTERWEST MANAGEMENT PARTNERS VI, LLC ("IMP VI")
<GROUP-MEMBERS>INTERWEST PARTNERS VI, LP ("IWP VI")
<GROUP-MEMBERS>PHILIP T. GIANOS ("GIANOS")
<GROUP-MEMBERS>ROBERT R. MOMSEN ("MOMSEN")
<GROUP-MEMBERS>W. SCOTT HEDRICK ("HEDRICK")
<GROUP-MEMBERS>W. STEPHEN HOLMES ("HOLMES")
<FILED-BY>
<COMPANY-DATA>
<CONFORMED-NAME>INTERWEST PARTNERS VI L P
<CIK>0001019182
<IRS-NUMBER>943247382
<STATE-OF-INCORPORATION>CA
<FISCAL-YEAR-END>1231
</COMPANY-DATA>
<FILING-VALUES>
<FORM-TYPE>SC 13G/A
</FILING-VALUES>
<BUSINESS-ADDRESS>
<STREET1>2710 SAND HILL ROAD
<STREET2>SECOND FLOOR
<CITY>MENLO PARK
<STATE>CA
<ZIP>94025
<PHONE>6508548585
</BUSINESS-ADDRESS>
</FILED-BY>
<SUBJECT-COMPANY>
<COMPANY-DATA>
<CONFORMED-NAME>AEROGEN INC
<CIK>0001039160
<ASSIGNED-SIC>3841
<IRS-NUMBER>330488580
<STATE-OF-INCORPORATION>DE
<FISCAL-YEAR-END>1231
</COMPANY-DATA>
<FILING-VALUES>
<FORM-TYPE>SC 13G/A
<ACT>34
<FILE-NUMBER>005-60561
<FILM-NUMBER>03556480
</FILING-VALUES>
<BUSINESS-ADDRESS>
<STREET1>1310 CORONADO DR
<CITY>SANTA CLARA
<STATE>CA
<ZIP>95054
<PHONE>4085432400
</BUSINESS-ADDRESS>
<MAIL-ADDRESS>
<STREET1>1310 ORLEANS DRIVE
<CITY>SUNNYVALE
<STATE>CA
<ZIP>94089
</MAIL-ADDRESS>
</SUBJECT-COMPANY>
<DOCUMENT>
<TYPE>SC 13G/A
<SEQUENCE>1
<FILENAME>p16613_sc13ga.txt
<DESCRIPTION>AMENDMENT NO. 2 TO SCHEDULE 13G
<TEXT>

                                                      --------------------------
                                                              OMB APPROVAL
                                                      --------------------------
                                                      OMB Number:      3235-0145
                                                      Expires: December 31, 2005
                                                      Estimated average burden
                                                      hours per response......11
                                                      --------------------------

                                  UNITED STATES
                       SECURITIES AND EXCHANGE COMMISSION
                              WASHINGTON, DC 20549

                                  ------------

                                  SCHEDULE 13G

           INFORMATION TO BE INCLUDED IN STATEMENTS FILED PURSUANT TO
              RULES 13d-1 (b), (c) AND (d) AND AMENDMENTS THERETO
                           FILED PURSUANT TO 13d-2 (b)
                               (Amendment No. 2)*

                                  Aerogen, Inc.
--------------------------------------------------------------------------------
                                (Name of Issuer)

                                  Common Stock
--------------------------------------------------------------------------------
                         (Title of Class of Securities)

                                   007779 10 1
--------------------------------------------------------------------------------
                                 (CUSIP Number)

                                   12-31-2002
--------------------------------------------------------------------------------
             (Date of Event Which Requires Filing of this Statement)

Check the  appropriate box to designate the rule pursuant to which this Schedule
is filed:

      |_|   Rule 13d-1(b)

      |_|   Rule 13d-1(c)

      |X|   Rule 13d-1(d)

*The  remainder of this cover page shall be filled out for a reporting  person's
initial filing on this form with respect to the subject class of securities, and
for any  subsequent  amendment  containing  information  which  would  alter the
disclosures provided in a prior cover page.

The information required in the remainder of this cover page shall not be deemed
to be "filed" for the purpose of Section 18 of the  Securities  Exchange  Act of
1934 ("Act") or otherwise  subject to the liabilities of that section of the Act
but  shall be  subject  to all other  provisions  of the Act  (however,  see the
Notes).


                               Page 1 of 16 pages
<PAGE>

CUSIP No. 007779 10 1                                         Page 2 of 16 Pages
--------------------------------------------------------------------------------
1     NAMES OF REPORTING PERSONS
      I.R.S. IDENTIFICATION NOS. OF ABOVE PERSONS (ENTITIES ONLY)

      InterWest Partners VI, LP
--------------------------------------------------------------------------------
2     CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP*
                                                                        (a)  |_|
                                                                        (b)  |_|
--------------------------------------------------------------------------------
3     SEC USE ONLY


--------------------------------------------------------------------------------
4     CITIZENSHIP OR PLACE OF ORGANIZATION

      California
--------------------------------------------------------------------------------
                  5     SOLE VOTING POWER

                        1,227,063
                        --------------------------------------------------------
  NUMBER OF       6     SHARED VOTING POWER
   SHARES
BENEFICIALLY            0
  OWNED BY              --------------------------------------------------------
    EACH          7     SOLE DISPOSITIVE POWER
  REPORTING
   PERSON               1,227,063
    WITH                --------------------------------------------------------
                  8     SHARED DISPOSITIVE POWER

                        0
--------------------------------------------------------------------------------
9     AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON

      1,227,063
--------------------------------------------------------------------------------
10    CHECK BOX IF THE AGGREGATE AMOUNT IN ROW (9) EXCLUDES CERTAIN SHARES*

      |_|
--------------------------------------------------------------------------------
11    PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW (9)

      6.0%
--------------------------------------------------------------------------------
12    TYPE OF REPORTING PERSON*

      PN
--------------------------------------------------------------------------------
                      *SEE INSTRUCTION BEFORE FILLING OUT!
<PAGE>

CUSIP No. 007779 10 1                                         Page 3 of 16 Pages
--------------------------------------------------------------------------------
1     NAMES OF REPORTING PERSONS
      I.R.S. IDENTIFICATION NOS. OF ABOVE PERSONS (ENTITIES ONLY)

      InterWest Investors VI, LP
--------------------------------------------------------------------------------
2     CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP*
                                                                        (a)  |_|
                                                                        (b)  |_|
--------------------------------------------------------------------------------
3     SEC USE ONLY


--------------------------------------------------------------------------------
4     CITIZENSHIP OR PLACE OF ORGANIZATION

      California
--------------------------------------------------------------------------------
                  5     SOLE VOTING POWER

                        37,486
                        --------------------------------------------------------
  NUMBER OF       6     SHARED VOTING POWER
   SHARES
BENEFICIALLY            0
  OWNED BY              --------------------------------------------------------
    EACH          7     SOLE DISPOSITIVE POWER
  REPORTING
   PERSON               37,486
    WITH                --------------------------------------------------------
                  8     SHARED DISPOSITIVE POWER

                        0
--------------------------------------------------------------------------------
9     AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON

      37,486
--------------------------------------------------------------------------------
10    CHECK BOX IF THE AGGREGATE AMOUNT IN ROW (9) EXCLUDES CERTAIN SHARES*

      |_|
--------------------------------------------------------------------------------
11    PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW (9)

      0.2%
--------------------------------------------------------------------------------
12    TYPE OF REPORTING PERSON*

      PN
--------------------------------------------------------------------------------
                      *SEE INSTRUCTION BEFORE FILLING OUT!
<PAGE>

CUSIP No. 007779 10 1                                         Page 4 of 16 Pages
--------------------------------------------------------------------------------
1     NAMES OF REPORTING PERSONS
      I.R.S. IDENTIFICATION NOS. OF ABOVE PERSONS (ENTITIES ONLY)

      InterWest Management Partners VI, LLC (the general partner of InterWest
      Partners VI, LP and InterWest Investors VI, LP)
--------------------------------------------------------------------------------
2     CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP*
                                                                        (a)  |_|
                                                                        (b)  |_|
--------------------------------------------------------------------------------
3     SEC USE ONLY


--------------------------------------------------------------------------------
4     CITIZENSHIP OR PLACE OF ORGANIZATION

      California
--------------------------------------------------------------------------------
                  5     SOLE VOTING POWER

                        1,264,549
                        --------------------------------------------------------
  NUMBER OF       6     SHARED VOTING POWER
   SHARES
BENEFICIALLY            0
  OWNED BY              --------------------------------------------------------
    EACH          7     SOLE DISPOSITIVE POWER
  REPORTING
   PERSON               1,264,549
    WITH                --------------------------------------------------------
                  8     SHARED DISPOSITIVE POWER

                        0
--------------------------------------------------------------------------------
9     AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON

      1,264,549
--------------------------------------------------------------------------------
10    CHECK BOX IF THE AGGREGATE AMOUNT IN ROW (9) EXCLUDES CERTAIN SHARES*

      |_|
--------------------------------------------------------------------------------
11    PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW (9)

      6.2%
--------------------------------------------------------------------------------
12    TYPE OF REPORTING PERSON*

      PN
--------------------------------------------------------------------------------
                      *SEE INSTRUCTION BEFORE FILLING OUT!
<PAGE>

CUSIP No. 007779 10 1                                         Page 5 of 16 Pages
--------------------------------------------------------------------------------
1     NAMES OF REPORTING PERSONS
      I.R.S. IDENTIFICATION NOS. OF ABOVE PERSONS (ENTITIES ONLY)

      Harvey B. Cash
      (a Managing Director of InterWest Management Partners VI, LLC)
--------------------------------------------------------------------------------
2     CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP*
                                                                        (a)  |_|
                                                                        (b)  |_|
--------------------------------------------------------------------------------
3     SEC USE ONLY


--------------------------------------------------------------------------------
4     CITIZENSHIP OR PLACE OF ORGANIZATION

      United States
--------------------------------------------------------------------------------
                  5     SOLE VOTING POWER

                        0
                        --------------------------------------------------------
  NUMBER OF       6     SHARED VOTING POWER
   SHARES
BENEFICIALLY            1,264,549
  OWNED BY              --------------------------------------------------------
    EACH          7     SOLE DISPOSITIVE POWER
  REPORTING
   PERSON               0
    WITH                --------------------------------------------------------
                  8     SHARED DISPOSITIVE POWER

                        1,264,549
--------------------------------------------------------------------------------
9     AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON

      1,264,549
--------------------------------------------------------------------------------
10    CHECK BOX IF THE AGGREGATE AMOUNT IN ROW (9) EXCLUDES CERTAIN SHARES*

      |_|
--------------------------------------------------------------------------------
11    PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW (9)

      6.2%
--------------------------------------------------------------------------------
12    TYPE OF REPORTING PERSON*

      IN
--------------------------------------------------------------------------------
                      *SEE INSTRUCTION BEFORE FILLING OUT!

Neither the filing of this  statement  on Schedule  13G nor any of its  contents
shall be  deemed to  constitute  an  admission  by Harvey B. Cash that he is the
beneficial  owner of any of the Common Stock  referred to herein for purposes of
Section 13(d) of the  Securities  Exchange Act of 1934,  as amended,  or for any
other purpose, and such beneficial ownership is expressly disclaimed,  except to
the extent of his pecuniary interest.
<PAGE>

CUSIP No. 007779 10 1                                         Page 6 of 16 Pages
--------------------------------------------------------------------------------
1     NAMES OF REPORTING PERSONS
      I.R.S. IDENTIFICATION NOS. OF ABOVE PERSONS (ENTITIES ONLY)

      Alan W. Crites
      (a Managing Director of InterWest Management Partners VI, LLC)
--------------------------------------------------------------------------------
2     CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP*
                                                                        (a)  |_|
                                                                        (b)  |_|
--------------------------------------------------------------------------------
3     SEC USE ONLY


--------------------------------------------------------------------------------
4     CITIZENSHIP OR PLACE OF ORGANIZATION

      United States
--------------------------------------------------------------------------------
                  5     SOLE VOTING POWER

                        0
                        --------------------------------------------------------
  NUMBER OF       6     SHARED VOTING POWER
   SHARES
BENEFICIALLY            1,264,549
  OWNED BY              --------------------------------------------------------
    EACH          7     SOLE DISPOSITIVE POWER
  REPORTING
   PERSON               0
    WITH                --------------------------------------------------------
                  8     SHARED DISPOSITIVE POWER

                        1,264,549
--------------------------------------------------------------------------------
9     AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON

      1,264,549
--------------------------------------------------------------------------------
10    CHECK BOX IF THE AGGREGATE AMOUNT IN ROW (9) EXCLUDES CERTAIN SHARES*

      |_|
--------------------------------------------------------------------------------
11    PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW (9)

      6.2%
--------------------------------------------------------------------------------
12    TYPE OF REPORTING PERSON*

      IN
--------------------------------------------------------------------------------
                      *SEE INSTRUCTION BEFORE FILLING OUT!

Neither the filing of this  statement  on Schedule  13G nor any of its  contents
shall be deemed to  constitute  an  admission  by Alan W.  Crites that he is the
beneficial  owner of any of the Common Stock  referred to herein for purposes of
Section 13(d) of the  Securities  Exchange Act of 1934,  as amended,  or for any
other purpose, and such beneficial ownership is expressly disclaimed,  except to
the extent of his pecuniary interest.
<PAGE>

CUSIP No. 007779 10 1                                         Page 7 of 16 Pages
--------------------------------------------------------------------------------
1     NAMES OF REPORTING PERSONS
      I.R.S. IDENTIFICATION NOS. OF ABOVE PERSONS (ENTITIES ONLY)

      Philip T. Gianos
      (a Managing Director of InterWest Management Partners VI, LLC)
--------------------------------------------------------------------------------
2     CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP*
                                                                        (a)  |_|
                                                                        (b)  |_|
--------------------------------------------------------------------------------
3     SEC USE ONLY


--------------------------------------------------------------------------------
4     CITIZENSHIP OR PLACE OF ORGANIZATION

      United States
--------------------------------------------------------------------------------
                  5     SOLE VOTING POWER

                        0
                        --------------------------------------------------------
  NUMBER OF       6     SHARED VOTING POWER
   SHARES
BENEFICIALLY            1,264,549
  OWNED BY              --------------------------------------------------------
    EACH          7     SOLE DISPOSITIVE POWER
  REPORTING
   PERSON               0
    WITH                --------------------------------------------------------
                  8     SHARED DISPOSITIVE POWER

                        1,264,549
--------------------------------------------------------------------------------
9     AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON

      1,264,549
--------------------------------------------------------------------------------
10    CHECK BOX IF THE AGGREGATE AMOUNT IN ROW (9) EXCLUDES CERTAIN SHARES*

      |_|
--------------------------------------------------------------------------------
11    PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW (9)

      6.2%
--------------------------------------------------------------------------------
12    TYPE OF REPORTING PERSON*

      IN
--------------------------------------------------------------------------------
                      *SEE INSTRUCTION BEFORE FILLING OUT!

Neither the filing of this  statement  on Schedule  13G nor any of its  contents
shall be deemed to  constitute  an  admission by Philip T. Gianos that he is the
beneficial  owner of any of the Common Stock  referred to herein for purposes of
Section 13(d) of the  Securities  Exchange Act of 1934,  as amended,  or for any
other purpose, and such beneficial ownership is expressly disclaimed,  except to
the extent of his pecuniary interest.
<PAGE>

CUSIP No. 007779 10 1                                         Page 8 of 16 Pages
--------------------------------------------------------------------------------
1     NAMES OF REPORTING PERSONS
      I.R.S. IDENTIFICATION NOS. OF ABOVE PERSONS (ENTITIES ONLY)

      W. Scott Hedrick
      (a Managing Director of InterWest Management Partners VI, LLC)
--------------------------------------------------------------------------------
2     CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP*
                                                                        (a)  |_|
                                                                        (b)  |_|
--------------------------------------------------------------------------------
3     SEC USE ONLY


--------------------------------------------------------------------------------
4     CITIZENSHIP OR PLACE OF ORGANIZATION

      United States
--------------------------------------------------------------------------------
                  5     SOLE VOTING POWER

                        0
                        --------------------------------------------------------
  NUMBER OF       6     SHARED VOTING POWER
   SHARES
BENEFICIALLY            1,264,549
  OWNED BY              --------------------------------------------------------
    EACH          7     SOLE DISPOSITIVE POWER
  REPORTING
   PERSON               0
    WITH                --------------------------------------------------------
                  8     SHARED DISPOSITIVE POWER

                        1,264,549
--------------------------------------------------------------------------------
9     AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON

      1,264,549
--------------------------------------------------------------------------------
10    CHECK BOX IF THE AGGREGATE AMOUNT IN ROW (9) EXCLUDES CERTAIN SHARES*

      |_|
--------------------------------------------------------------------------------
11    PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW (9)

      6.2%
--------------------------------------------------------------------------------
12    TYPE OF REPORTING PERSON*

      IN
--------------------------------------------------------------------------------
                      *SEE INSTRUCTION BEFORE FILLING OUT!

Neither the filing of this  statement  on Schedule  13G nor any of its  contents
shall be deemed to  constitute  an admission by W. Scott  Hedrick that he is the
beneficial  owner of any of the Common Stock  referred to herein for purposes of
Section 13(d) of the  Securities  Exchange Act of 1934,  as amended,  or for any
other purpose, and such beneficial ownership is expressly disclaimed,  except to
the extent of his pecuniary interest.
<PAGE>

CUSIP No. 007779 10 1                                         Page 9 of 16 Pages
--------------------------------------------------------------------------------
1     NAMES OF REPORTING PERSONS
      I.R.S. IDENTIFICATION NOS. OF ABOVE PERSONS (ENTITIES ONLY)

      W. Stephen Holmes
      (a Managing Director of InterWest Management Partners VI, LLC)
--------------------------------------------------------------------------------
2     CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP*
                                                                        (a)  |_|
                                                                        (b)  |_|
--------------------------------------------------------------------------------
3     SEC USE ONLY


--------------------------------------------------------------------------------
4     CITIZENSHIP OR PLACE OF ORGANIZATION

      United States
--------------------------------------------------------------------------------
                  5     SOLE VOTING POWER

                        0
                        --------------------------------------------------------
  NUMBER OF       6     SHARED VOTING POWER
   SHARES
BENEFICIALLY            1,264,549
  OWNED BY              --------------------------------------------------------
    EACH          7     SOLE DISPOSITIVE POWER
  REPORTING
   PERSON               0
    WITH                --------------------------------------------------------
                  8     SHARED DISPOSITIVE POWER

                        1,264,549
--------------------------------------------------------------------------------
9     AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON

      1,264,549
--------------------------------------------------------------------------------
10    CHECK BOX IF THE AGGREGATE AMOUNT IN ROW (9) EXCLUDES CERTAIN SHARES*

      |_|
--------------------------------------------------------------------------------
11    PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW (9)

      6.2%
--------------------------------------------------------------------------------
12    TYPE OF REPORTING PERSON*

      IN
--------------------------------------------------------------------------------
                      *SEE INSTRUCTION BEFORE FILLING OUT!

Neither the filing of this  statement  on Schedule  13G nor any of its  contents
shall be deemed to constitute  an admission by W. Stephen  Holmes that he is the
beneficial  owner of any of the Common Stock  referred to herein for purposes of
Section 13(d) of the  Securities  Exchange Act of 1934,  as amended,  or for any
other purpose, and such beneficial ownership is expressly disclaimed,  except to
the extent of his pecuniary interest.
<PAGE>

CUSIP No. 007779 10 1                                        Page 10 of 16 Pages
--------------------------------------------------------------------------------
1     NAMES OF REPORTING PERSONS
      I.R.S. IDENTIFICATION NOS. OF ABOVE PERSONS (ENTITIES ONLY)

      Gilbert H. Kliman
      (a Venture Member of InterWest Management Partners VI, LLC)
--------------------------------------------------------------------------------
2     CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP*
                                                                        (a)  |_|
                                                                        (b)  |_|
--------------------------------------------------------------------------------
3     SEC USE ONLY


--------------------------------------------------------------------------------
4     CITIZENSHIP OR PLACE OF ORGANIZATION

      United States
--------------------------------------------------------------------------------
                  5     SOLE VOTING POWER

                        0
                        --------------------------------------------------------
  NUMBER OF       6     SHARED VOTING POWER
   SHARES
BENEFICIALLY            1,264,549
  OWNED BY              --------------------------------------------------------
    EACH          7     SOLE DISPOSITIVE POWER
  REPORTING
   PERSON               0
    WITH                --------------------------------------------------------
                  8     SHARED DISPOSITIVE POWER

                        1,264,549
--------------------------------------------------------------------------------
9     AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON

      1,264,549
--------------------------------------------------------------------------------
10    CHECK BOX IF THE AGGREGATE AMOUNT IN ROW (9) EXCLUDES CERTAIN SHARES*

      |_|
--------------------------------------------------------------------------------
11    PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW (9)

      6.2%
--------------------------------------------------------------------------------
12    TYPE OF REPORTING PERSON*

      IN
--------------------------------------------------------------------------------
                      *SEE INSTRUCTION BEFORE FILLING OUT!

Neither the filing of this  statement  on Schedule  13G nor any of its  contents
shall be deemed to  constitute  an admission by Gilbert H. Kliman that he is the
beneficial  owner of any of the Common Stock  referred to herein for purposes of
Section 13(d) of the  Securities  Exchange Act of 1934,  as amended,  or for any
other purpose, and such beneficial ownership is expressly disclaimed,  except to
the extent of his pecuniary interest.
<PAGE>

CUSIP No. 007779 10 1                                        Page 11 of 16 Pages
--------------------------------------------------------------------------------
1     NAMES OF REPORTING PERSONS
      I.R.S. IDENTIFICATION NOS. OF ABOVE PERSONS (ENTITIES ONLY)

      Robert R. Momsen
      (a Managing Director of InterWest Management Partners VI, LLC)
--------------------------------------------------------------------------------
2     CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP*
                                                                        (a)  |_|
                                                                        (b)  |_|
--------------------------------------------------------------------------------
3     SEC USE ONLY


--------------------------------------------------------------------------------
4     CITIZENSHIP OR PLACE OF ORGANIZATION

      United States
--------------------------------------------------------------------------------
                  5     SOLE VOTING POWER

                        0
                        --------------------------------------------------------
  NUMBER OF       6     SHARED VOTING POWER
   SHARES
BENEFICIALLY            1,264,549
  OWNED BY              --------------------------------------------------------
    EACH          7     SOLE DISPOSITIVE POWER
  REPORTING
   PERSON               0
    WITH                --------------------------------------------------------
                  8     SHARED DISPOSITIVE POWER

                        1,264,549
--------------------------------------------------------------------------------
9     AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON

      1,264,549
--------------------------------------------------------------------------------
10    CHECK BOX IF THE AGGREGATE AMOUNT IN ROW (9) EXCLUDES CERTAIN SHARES*

      |_|
--------------------------------------------------------------------------------
11    PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW (9)

      6.2%
--------------------------------------------------------------------------------
12    TYPE OF REPORTING PERSON*

      IN
--------------------------------------------------------------------------------
                      *SEE INSTRUCTION BEFORE FILLING OUT!

Neither the filing of this  statement  on Schedule  13G nor any of its  contents
shall be deemed to  constitute  an  admission by Robert R. Momsen that he is the
beneficial  owner of any of the Common Stock  referred to herein for purposes of
Section 13(d) of the  Securities  Exchange Act of 1934,  as amended,  or for any
other purpose, and such beneficial ownership is expressly disclaimed,  except to
the extent of his pecuniary interest.
<PAGE>

CUSIP No. 007779 10 1                                        Page 12 of 16 Pages
--------------------------------------------------------------------------------
1     NAMES OF REPORTING PERSONS
      I.R.S. IDENTIFICATION NOS. OF ABOVE PERSONS (ENTITIES ONLY)

      Arnold L. Oronsky
      (a Managing Director of InterWest Management Partners VI, LLC)
--------------------------------------------------------------------------------
2     CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP*
                                                                        (a)  |_|
                                                                        (b)  |_|
--------------------------------------------------------------------------------
3     SEC USE ONLY


--------------------------------------------------------------------------------
4     CITIZENSHIP OR PLACE OF ORGANIZATION

      United States
--------------------------------------------------------------------------------
                  5     SOLE VOTING POWER

                        0
                        --------------------------------------------------------
  NUMBER OF       6     SHARED VOTING POWER
   SHARES
BENEFICIALLY            1,264,549
  OWNED BY              --------------------------------------------------------
    EACH          7     SOLE DISPOSITIVE POWER
  REPORTING
   PERSON               0
    WITH                --------------------------------------------------------
                  8     SHARED DISPOSITIVE POWER

                        1,264,549
--------------------------------------------------------------------------------
9     AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON

      1,264,549
--------------------------------------------------------------------------------
10    CHECK BOX IF THE AGGREGATE AMOUNT IN ROW (9) EXCLUDES CERTAIN SHARES*

      |_|
--------------------------------------------------------------------------------
11    PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW (9)

      6.2%
--------------------------------------------------------------------------------
12    TYPE OF REPORTING PERSON*

      IN
--------------------------------------------------------------------------------
                      *SEE INSTRUCTION BEFORE FILLING OUT!

* Neither the filing of this  statement  on Schedule 13G nor any of its contents
shall be deemed to  constitute  an admission by Arnold L. Oronsky that he is the
beneficial  owner of any of the Common Stock  referred to herein for purposes of
Section 13(d) of the  Securities  Exchange Act of 1934,  as amended,  or for any
other purpose, and such beneficial ownership is expressly disclaimed,  except to
the extent of his pecuniary interest.
<PAGE>

Item 1.

(a)   Name of Issuer: Aerogen, Inc. ("Issuer")

(b)   Address of Issuer's Principal Executive Offices:

      2071 Stierlin Court
      Mountain View, CA 94043

Item 2.

(a)   Name of Person(s) Filing:

      InterWest Partners VI, LP ("IWP VI")
      InterWest Investors VI, LP ("II VI")
      InterWest Management Partners VI, LLC ("IMP VI")
      Harvey B. Cash ("Cash")
      Alan W. Crites ("Crites")
      Philip T. Gianos ("Gianos")
      W. Scott Hedrick ("Hedrick")
      W. Stephen Holmes ("Holmes")
      Gilbert H. Kliman ("Kliman")
      Robert R. Momsen ("Momsen")
      Arnold L. Oronsky ("Oronsky")

(b)   Address of Principal Business Office or, if none, Residence:

      2710 Sand Hill Road
      Second Floor
      Menlo Park, CA 94025

(c)   Citizenship/Place of Organization:

      IWP VI:           California
      II VI:            California
      IMP VI:           California
      Cash:             United States
      Crites:           United States
      Gianos:           United States
      Hedrick:          United States
      Holmes:           United States
      Kliman:           United States
      Momsen:           United States
      Oronsky:          United States

(d)   Title of Class of Securities: Common Stock

(e)   CUSIP Number: 007779 10 1

Item 3. Not applicable.


                              Page 13 of 16 pages
<PAGE>

Item 4. Ownership.

================================================================================
                                                                        All
                                                                       Other
                        IWP VI            II VI       IMP VI        Individuals*
--------------------------------------------------------------------------------
(a)    Beneficial
       Ownership       1,227,063         37,486      1,264,549        1,264,549
--------------------------------------------------------------------------------
(b)    Percentage
       of Class             6.0%           0.2%           6.2%             6.2%
--------------------------------------------------------------------------------
(c)    Sole Voting
       Power           1,227,063         37,486      1,264,549                0
--------------------------------------------------------------------------------
       Shared
       Voting
       Power                   0              0              0        1,264,549
--------------------------------------------------------------------------------
       Sole
       Dispositive
       Power           1,227,063         37,486      1,264,549                0
--------------------------------------------------------------------------------
       Shared
       Dispositive
       Power                   0              0              0        1,264,549
================================================================================

*Individuals included in this column are Cash, Crites, Gianos, Hedrick,  Holmes,
Momsen and Oronsky,  all of whom are Managing Directors of IMP VI. Also included
in this column is Kliman who is a Venture Member of IMP VI.

Item 5. Ownership of Five Percent or Less of a Class

Not applicable.

Item 6. Ownership of More than Five Percent on Behalf of Another Person

Under  certain  circumstances  set  forth  in the  limited  liability  operating
agreement  of IMP VI, the members of such  limited  liability  company  have the
right to receive  dividends  from,  or the proceeds from the sale of, the Common
Stock of Issuer beneficially owned by such limited liability company.

Item 7.  Identification  and Classification of the Subsidiary Which Acquired the
         Security Being Reported on By the Parent Holding Company.

Not applicable.

Item 8. Identification and Classification of Members of the Group

No   reporting   person  is  a  member  of  a  group  as   defined   in  section
240.13d-1(b)(1)(iii)(H) of the Act.

Item 9. Notice of Dissolution of Group

Not applicable.

Item 10. Certification

Not applicable

EXHIBITS

A. Joint Filing Statement


                              Page 14 of 16 pages
<PAGE>

                                    SIGNATURE

After  reasonable  inquiry and to the best of my knowledge and belief, I certify
that the information set forth in this statement is true, complete and correct.

Date: February ____, 2003

INTERWEST PARTNERS VI, LP

By: InterWest Management Partners VI, LLC           By: /s/ Harvey B. Cash
                                                        ------------------------
                                                    Name: Harvey B. Cash
    By: /s/ W. Stephen Holmes
        ------------------------------------        By: /s/ Alan W. Crites
        Managing Director                               ------------------------
                                                    Name: Alan W. Crites

INTERWEST INVESTORS VI, LP                          By: /s/ Philip T. Gianos
                                                        ------------------------
                                                    Name: Philip T. Gianos
By: InterWest Management Partners VI, LLC
                                                    By: /s/ W. Scott Hedrick
    By: /s/ W. Stephen Holmes                           ------------------------
        ------------------------------------        Name: W. Scott Hedrick
               Managing Director
                                                    By: /s/ W. Stephen Holmes
INTERWEST MANAGEMENT PARTNERS VI, LLC                   ------------------------
                                                    Name: W. Stephen Holmes

By: /s/ W. Stephen Holmes                           By: /s/ Gilbert H. Kliman
    ----------------------------------------            ------------------------
    Managing Director                               Name: Gilbert H. Kliman

                                                    By: /s/ Robert R. Momsen
                                                        ------------------------
                                                    Name: Robert R. Momsen

                                                    By: /s/ Arnold L. Oronsky
                                                        ------------------------
                                                    Name: Arnold L. Oronsky


                              Page 15 of 16 pages
<PAGE>

                                    EXHIBIT A

                             JOINT FILING STATEMENT

We, the undersigned, hereby express our agreement that the attached Schedule 13G
is filed on behalf of each of us.

Date: February ____, 2003

INTERWEST PARTNERS VI, LP

By: InterWest Management Partners VI, LLC           By: /s/ Harvey B. Cash
                                                        ------------------------
                                                    Name: Harvey B. Cash
    By: /s/ W. Stephen Holmes
        ------------------------------------        By: /s/ Alan W. Crites
        Managing Director                               ------------------------
                                                    Name: Alan W. Crites

INTERWEST INVESTORS VI, LP                          By: /s/ Philip T. Gianos
                                                        ------------------------
                                                    Name: Philip T. Gianos
By: InterWest Management Partners VI, LLC
                                                    By: /s/ W. Scott Hedrick
    By: /s/ W. Stephen Holmes                           ------------------------
        ------------------------------------        Name: W. Scott Hedrick
               Managing Director
                                                    By: /s/ W. Stephen Holmes
INTERWEST MANAGEMENT PARTNERS VI, LLC                   ------------------------
                                                    Name: W. Stephen Holmes

By: /s/ W. Stephen Holmes                           By: /s/ Gilbert H. Kliman
    ----------------------------------------            ------------------------
    Managing Director                               Name: Gilbert H. Kliman

                                                    By: /s/ Robert R. Momsen
                                                        ------------------------
                                                    Name: Robert R. Momsen

                                                    By: /s/ Arnold L. Oronsky
                                                        ------------------------
                                                    Name: Arnold L. Oronsky


                              Page 16 of 16 pages


</TEXT>
</DOCUMENT>
</SUBMISSION>
