<SUBMISSION>
<ACCESSION-NUMBER>0001193125-06-167782
<TYPE>S-8
<PUBLIC-DOCUMENT-COUNT>3
<FILING-DATE>20060809
<DATE-OF-FILING-DATE-CHANGE>20060809
<EFFECTIVENESS-DATE>20060809
<FILER>
<COMPANY-DATA>
<CONFORMED-NAME>CERUS CORP
<CIK>0001020214
<ASSIGNED-SIC>2836
<IRS-NUMBER>680262011
<STATE-OF-INCORPORATION>DE
<FISCAL-YEAR-END>1231
</COMPANY-DATA>
<FILING-VALUES>
<FORM-TYPE>S-8
<ACT>33
<FILE-NUMBER>333-136452
<FILM-NUMBER>061017956
</FILING-VALUES>
<BUSINESS-ADDRESS>
<STREET1>2411 STANWELL DR
<CITY>CONCORD
<STATE>CA
<ZIP>94520
<PHONE>9252886000
</BUSINESS-ADDRESS>
<MAIL-ADDRESS>
<STREET1>2525 STANWELL DRIVE
<STREET2>STE 300
<CITY>CONCORD
<STATE>CA
<ZIP>94520
</MAIL-ADDRESS>
<FORMER-COMPANY>
<FORMER-CONFORMED-NAME>CERUS TECHNOLOGIES INC
<DATE-CHANGED>19960731
</FORMER-COMPANY>
</FILER>
<DOCUMENT>
<TYPE>S-8
<SEQUENCE>1
<FILENAME>ds8.htm
<DESCRIPTION>FORM S-8
<TEXT>
<HTML><HEAD>
<TITLE>Form S-8</TITLE>
</HEAD>
 <BODY BGCOLOR="WHITE">
 <P STYLE="margin-top:0px;margin-bottom:0px" ALIGN="center"><FONT FACE="Times New Roman" SIZE="2"><B>As filed with the Securities and Exchange Commission on August&nbsp;9, 2006 </B></FONT></P> <P
STYLE="margin-top:0px;margin-bottom:0px" ALIGN="right"><FONT FACE="Times New Roman" SIZE="2"><B>Registration No.&nbsp;333-&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; </B></FONT></P><HR SIZE="3" NOSHADE COLOR="#000000"
ALIGN="left"> <P STYLE="margin-top:3px;margin-bottom:0px" ALIGN="center"><FONT FACE="Times New Roman" SIZE="5"><B>SECURITIES AND EXCHANGE COMMISSION </B></FONT></P> <P STYLE="margin-top:0px;margin-bottom:0px" ALIGN="center"><FONT
FACE="Times New Roman" SIZE="3"><B>Washington, D.C. 20549 </B></FONT></P> <P STYLE="font-size:12px;margin-top:0px;margin-bottom:0px">&nbsp;</P><HR WIDTH="17%" SIZE="1" NOSHADE COLOR="#000000"> <P STYLE="margin-top:12px;margin-bottom:0px"
ALIGN="center"><FONT FACE="Times New Roman" SIZE="5"><B>FORM S-8 </B></FONT></P> <P STYLE="margin-top:12px;margin-bottom:0px" ALIGN="center"><FONT FACE="Times New Roman" SIZE="5"><B>REGISTRATION STATEMENT </B></FONT></P> <P
STYLE="margin-top:0px;margin-bottom:0px" ALIGN="center"><FONT FACE="Times New Roman" SIZE="3"><B><I>UNDER </I></B></FONT></P> <P STYLE="margin-top:0px;margin-bottom:0px" ALIGN="center"><FONT FACE="Times New Roman" SIZE="3"><B><I>THE SECURITIES ACT
OF 1933 </I></B></FONT></P> <P STYLE="font-size:12px;margin-top:0px;margin-bottom:0px">&nbsp;</P><HR WIDTH="17%" SIZE="1" NOSHADE COLOR="#000000"> <P STYLE="margin-top:12px;margin-bottom:0px" ALIGN="center"><FONT FACE="Times New Roman"
SIZE="6"><B>CERUS CORPORATION </B></FONT></P> <P STYLE="margin-top:0px;margin-bottom:0px" ALIGN="center"><FONT FACE="Times New Roman" SIZE="1"><B>(Exact name of registrant as specified in its charter) </B></FONT></P> <P
STYLE="font-size:12px;margin-top:0px;margin-bottom:0px">&nbsp;</P><HR WIDTH="17%" SIZE="1" NOSHADE COLOR="#000000"> <P STYLE="font-size:12px;margin-top:0px;margin-bottom:0px">&nbsp;</P>
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<TD WIDTH="50%"></TD>
<TD VALIGN="bottom" WIDTH="2%"></TD>
<TD WIDTH="48%"></TD></TR>
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<TD VALIGN="top" ALIGN="center"><FONT FACE="Times New Roman" SIZE="2"><B>Delaware</B></FONT></TD>
<TD VALIGN="bottom"><FONT SIZE="1">&nbsp;</FONT></TD>
<TD VALIGN="top" ALIGN="center"><FONT FACE="Times New Roman" SIZE="2"><B>68-0262011</B></FONT></TD></TR>
<TR>
<TD VALIGN="top" ALIGN="center"><FONT FACE="Times New Roman" SIZE="1"><B>(State of Incorporation)</B></FONT></TD>
<TD VALIGN="bottom"><FONT SIZE="1">&nbsp;</FONT></TD>
<TD VALIGN="top" ALIGN="center"><FONT FACE="Times New Roman" SIZE="1"><B>(I.R.S. Employer Identification No.)</B></FONT></TD></TR>
</TABLE> <P STYLE="margin-top:12px;margin-bottom:0px" ALIGN="center"><FONT FACE="Times New Roman" SIZE="2"><B>2411 S<SMALL>TANWELL</SMALL> D<SMALL>RIVE</SMALL> </B></FONT></P> <P
STYLE="margin-top:0px;margin-bottom:0px" ALIGN="center"><FONT FACE="Times New Roman" SIZE="2"><B>C<SMALL>ONCORD</SMALL>, C<SMALL>ALIFORNIA</SMALL> 94520 </B></FONT></P> <P STYLE="margin-top:0px;margin-bottom:0px" ALIGN="center"><FONT
FACE="Times New Roman" SIZE="1"><B>(Address of principal executive offices) </B></FONT></P> <P STYLE="font-size:12px;margin-top:0px;margin-bottom:0px">&nbsp;</P><HR WIDTH="17%" SIZE="1" NOSHADE COLOR="#000000"> <P
STYLE="margin-top:12px;margin-bottom:0px" ALIGN="center"><FONT FACE="Times New Roman" SIZE="2"><B>1999 EQUITY INCENTIVE PLAN </B></FONT></P> <P STYLE="margin-top:0px;margin-bottom:0px" ALIGN="center"><FONT FACE="Times New Roman" SIZE="1"><B>(Full
title of the plans) </B></FONT></P> <P STYLE="font-size:12px;margin-top:0px;margin-bottom:0px">&nbsp;</P><HR WIDTH="17%" SIZE="1" NOSHADE COLOR="#000000"> <P STYLE="margin-top:12px;margin-bottom:0px" ALIGN="center"><FONT FACE="Times New Roman"
SIZE="2"><B>CLAES GLASSELL </B></FONT></P> <P STYLE="margin-top:0px;margin-bottom:0px" ALIGN="center"><FONT FACE="Times New Roman" SIZE="2"><B>PRESIDENT AND CHIEF EXECUTIVE OFFICER </B></FONT></P> <P STYLE="margin-top:0px;margin-bottom:0px"
ALIGN="center"><FONT FACE="Times New Roman" SIZE="2"><B>CERUS CORPORATION </B></FONT></P> <P STYLE="margin-top:0px;margin-bottom:0px" ALIGN="center"><FONT FACE="Times New Roman" SIZE="2"><B>2411 STANWELL DRIVE </B></FONT></P> <P
STYLE="margin-top:0px;margin-bottom:0px" ALIGN="center"><FONT FACE="Times New Roman" SIZE="2"><B>CONCORD, CALIFORNIA 94520 </B></FONT></P> <P STYLE="margin-top:0px;margin-bottom:0px" ALIGN="center"><FONT FACE="Times New Roman" SIZE="2"><B>(925)
288-6000 </B></FONT></P> <P STYLE="margin-top:0px;margin-bottom:0px" ALIGN="center"><FONT FACE="Times New Roman" SIZE="1"><B>(Name, address, including zip code, and telephone number, including area code, of agent for service) </B></FONT></P> <P
STYLE="font-size:12px;margin-top:0px;margin-bottom:0px">&nbsp;</P><HR WIDTH="17%" SIZE="1" NOSHADE COLOR="#000000"> <P STYLE="margin-top:12px;margin-bottom:0px" ALIGN="center"><FONT FACE="Times New Roman" SIZE="2"><B><I>Copies to:
</I></B></FONT></P> <P STYLE="margin-top:0px;margin-bottom:0px" ALIGN="center"><FONT FACE="Times New Roman" SIZE="2"><B>ROBERT L. JONES, ESQ. </B></FONT></P> <P STYLE="margin-top:0px;margin-bottom:0px" ALIGN="center"><FONT FACE="Times New Roman"
SIZE="2"><B>COOLEY GODWARD LLP </B></FONT></P> <P STYLE="margin-top:0px;margin-bottom:0px" ALIGN="center"><FONT FACE="Times New Roman" SIZE="2"><B>FIVE PALO ALTO SQUARE </B></FONT></P> <P STYLE="margin-top:0px;margin-bottom:0px" ALIGN="center"><FONT
FACE="Times New Roman" SIZE="2"><B>3000 EL CAMINO REAL </B></FONT></P> <P STYLE="margin-top:0px;margin-bottom:0px" ALIGN="center"><FONT FACE="Times New Roman" SIZE="2"><B>PALO ALTO, CALIFORNIA 94306 </B></FONT></P> <P
STYLE="margin-top:0px;margin-bottom:0px" ALIGN="center"><FONT FACE="Times New Roman" SIZE="2"><B>(650) 843-5000 </B></FONT></P> <P STYLE="font-size:12px;margin-top:0px;margin-bottom:0px">&nbsp;</P><HR WIDTH="17%" SIZE="1" NOSHADE COLOR="#000000"> <P
STYLE="margin-top:12px;margin-bottom:0px" ALIGN="center"><FONT FACE="Times New Roman" SIZE="2"><B>CALCULATION OF REGISTRATION FEE </B></FONT></P> <P STYLE="font-size:12px;margin-top:0px;margin-bottom:0px">&nbsp;</P><HR SIZE="3" NOSHADE
COLOR="#000000" ALIGN="left">
<TABLE CELLSPACING="0" CELLPADDING="0" WIDTH="100%" BORDER="0" ALIGN="center">

<TR>
<TD WIDTH="49%"></TD>
<TD VALIGN="bottom" WIDTH="7%"></TD>
<TD></TD>
<TD VALIGN="bottom" WIDTH="7%"></TD>
<TD></TD>
<TD></TD>
<TD VALIGN="bottom" WIDTH="7%"></TD>
<TD></TD>
<TD></TD>
<TD VALIGN="bottom" WIDTH="7%"></TD>
<TD></TD>
<TD></TD></TR>
<TR>
<TD VALIGN="bottom" NOWRAP ALIGN="center" STYLE="BORDER-BOTTOM:1px solid #000000"><FONT FACE="Times New Roman" SIZE="1"><B>Title of Securities to be Registered</B></FONT></TD>
<TD VALIGN="bottom" STYLE="BORDER-BOTTOM:1px solid #000000"><FONT SIZE="1">&nbsp;&nbsp;</FONT></TD>
<TD VALIGN="bottom" NOWRAP ALIGN="center" STYLE="BORDER-BOTTOM:1px solid #000000"><FONT FACE="Times New Roman" SIZE="1"><B>Amount to be<BR>Registered(1)</B></FONT></TD>
<TD VALIGN="bottom" STYLE="BORDER-BOTTOM:1px solid #000000"><FONT SIZE="1">&nbsp;&nbsp;</FONT></TD>
<TD VALIGN="bottom" COLSPAN="2" NOWRAP ALIGN="center" STYLE="BORDER-BOTTOM:1px solid #000000"><FONT FACE="Times New Roman" SIZE="1"><B>Proposed&nbsp;Maximum<BR>Offering&nbsp;Price&nbsp;Per<BR>Share (2)</B></FONT></TD>
<TD VALIGN="bottom" STYLE="BORDER-BOTTOM:1px solid #000000"><FONT SIZE="1">&nbsp;&nbsp;</FONT></TD>
<TD VALIGN="bottom" COLSPAN="2" NOWRAP ALIGN="center" STYLE="BORDER-BOTTOM:1px solid #000000"><FONT FACE="Times New Roman" SIZE="1"><B>Proposed&nbsp;Maximum<BR>Aggregate&nbsp;Offering<BR>Price (2)</B></FONT></TD>
<TD VALIGN="bottom" STYLE="BORDER-BOTTOM:1px solid #000000"><FONT SIZE="1">&nbsp;&nbsp;</FONT></TD>
<TD VALIGN="bottom" COLSPAN="2" NOWRAP ALIGN="center" STYLE="BORDER-BOTTOM:1px solid #000000"><FONT FACE="Times New Roman" SIZE="1"><B>Amount of<BR>Registration&nbsp;Fee</B></FONT></TD></TR>
<TR>
<TD VALIGN="top"> <P STYLE="margin-left:1.00em; text-indent:-1.00em"><FONT FACE="Times New Roman" SIZE="2">Shares of Common Stock, par value $.001 per share</FONT></P></TD>
<TD VALIGN="bottom"><FONT SIZE="1">&nbsp;&nbsp;</FONT></TD>
<TD VALIGN="bottom" ALIGN="right"><FONT FACE="Times New Roman" SIZE="2">800,000</FONT></TD>
<TD VALIGN="bottom"><FONT SIZE="1">&nbsp;&nbsp;</FONT></TD>
<TD VALIGN="bottom"><FONT FACE="Times New Roman" SIZE="2">$</FONT></TD>
<TD VALIGN="bottom" ALIGN="right"><FONT FACE="Times New Roman" SIZE="2">5.87</FONT></TD>
<TD VALIGN="bottom"><FONT SIZE="1">&nbsp;&nbsp;</FONT></TD>
<TD VALIGN="bottom"><FONT FACE="Times New Roman" SIZE="2">$</FONT></TD>
<TD VALIGN="bottom" ALIGN="right"><FONT FACE="Times New Roman" SIZE="2">4,696,000.00</FONT></TD>
<TD VALIGN="bottom"><FONT SIZE="1">&nbsp;&nbsp;</FONT></TD>
<TD VALIGN="bottom"><FONT FACE="Times New Roman" SIZE="2">$</FONT></TD>
<TD VALIGN="bottom" ALIGN="right"><FONT FACE="Times New Roman" SIZE="2">502.47</FONT></TD></TR>
</TABLE><HR SIZE="3" NOSHADE COLOR="#000000" ALIGN="left">
<TABLE STYLE="BORDER-COLLAPSE:COLLAPSE" BORDER="0" CELLPADDING="0" CELLSPACING="0" WIDTH="100%">
<TR>
<TD WIDTH="4%" VALIGN="top" ALIGN="left"><FONT FACE="Times New Roman" SIZE="2">(1)</FONT></TD>
<TD ALIGN="left" VALIGN="top"><FONT FACE="Times New Roman" SIZE="2">This Registration Statement shall cover any additional shares of Common Stock which become issuable under the Issuer&#146;s 1999 Equity Incentive Plan (the &#147;Plan&#148;) set
forth herein by reason of any stock dividend, stock split, recapitalization or any other similar transaction without receipt of consideration which results in an increase in the number of shares of the outstanding Common Stock of Cerus Corporation
(the &#147;Company&#148; or &#147;Registrant&#148;). </FONT></TD></TR></TABLE>
<TABLE STYLE="BORDER-COLLAPSE:COLLAPSE" BORDER="0" CELLPADDING="0" CELLSPACING="0" WIDTH="100%">
<TR>
<TD WIDTH="4%" VALIGN="top" ALIGN="left"><FONT FACE="Times New Roman" SIZE="2">(2)</FONT></TD>
<TD ALIGN="left" VALIGN="top"><FONT FACE="Times New Roman" SIZE="2">Estimated solely for the purpose of calculating the amount of the registration fee. The offering price per share and aggregate offering price are based upon the average of the high
and low prices of the Company&#146;s Common Stock as reported on the Nasdaq Global Market on August&nbsp;3, 2006 for shares available for future grant pursuant to the Plan (pursuant to Rule 457(c) under the Act). </FONT></TD></TR></TABLE> <P
STYLE="font-size:6px;margin-top:0px;margin-bottom:0px">&nbsp;</P><HR SIZE="3" NOSHADE COLOR="#000000" ALIGN="left">

<p Style='page-break-before:always'>
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 <P STYLE="margin-top:0px;margin-bottom:0px" ALIGN="center"><FONT FACE="Times New Roman" SIZE="2"><B>INCORPORATION OF CERTAIN DOCUMENTS BY REFERENCE </B></FONT></P> <P
STYLE="margin-top:12px;margin-bottom:0px; text-indent:4%"><FONT FACE="Times New Roman" SIZE="2">The following documents filed by Cerus Corporation (the &#147;Company&#148;) with the Securities and Exchange Commission (the &#147;SEC&#148;) are
incorporated by reference into this Registration Statement: </FONT></P> <P STYLE="margin-top:6px;margin-bottom:0px; margin-left:4%; text-indent:4%"><FONT FACE="Times New Roman" SIZE="2"><B>(a)</B> The contents of Registration Statements on
Form&nbsp;S-8 Nos.&nbsp;333-27097, 333-74991, 333-84497, 333-42588, 333-63132, 333-92254, 333-109170, 333-125043 and 333-127541, filed with the Securities and Exchange Commission on May&nbsp;14, 1997,&nbsp;March&nbsp;24, 1999,&nbsp;August&nbsp;4,
1999,&nbsp;July&nbsp;28, 2000,&nbsp;June&nbsp;15, 2001&nbsp;July&nbsp;11, 2002,&nbsp;September&nbsp;26, 2003,&nbsp;May&nbsp;19, 2005 and August&nbsp;15, 2005, respectively, are incorporated by reference herein. </FONT></P> <P
STYLE="margin-top:6px;margin-bottom:0px; margin-left:4%; text-indent:4%"><FONT FACE="Times New Roman" SIZE="2"><B>(b)</B> The Company&#146;s Annual Report on Form 10-K for the year ended December&nbsp;31, 2005 and filed with the SEC on
February&nbsp;27, 2006, the Company&#146;s Quarterly Report on Form 10-Q for the quarter ended March&nbsp;31, 2006 and filed with the SEC on May&nbsp;2, 2006, the Company&#146;s Quarterly Report on Form 10-Q for the quarter ended June&nbsp;30, 2006
and filed with the SEC on August&nbsp;4, 2006 and the Company&#146;s Current Reports on Form 8-K, filed with the SEC on January&nbsp;4, 2006,&nbsp;February&nbsp;13, 2006,&nbsp;February&nbsp;24, 2006,&nbsp;February&nbsp;27, 2006,&nbsp;March&nbsp;17,
2006,&nbsp;March&nbsp;27, 2006,&nbsp;March&nbsp;30, 2006,&nbsp;May&nbsp;2, 2006,&nbsp;June&nbsp;9, 2006 and August&nbsp;3, 2006. </FONT></P> <P STYLE="margin-top:6px;margin-bottom:0px; margin-left:4%; text-indent:4%"><FONT FACE="Times New Roman"
SIZE="2"><B>(c)</B> The description of the Company&#146;s Common Stock which is contained in a registration statement on Form&nbsp;8-A filed with the SEC under the Securities Exchange Act of 1934 (the &#147;Exchange Act&#148;), including any
amendment or report filed for the purpose of updating such description. </FONT></P> <P STYLE="margin-top:12px;margin-bottom:0px; text-indent:4%"><FONT FACE="Times New Roman" SIZE="2">All reports and other documents subsequently filed by the Company
pursuant to Sections 13(a), 13(c), 14 and 15(d) of the Exchange Act prior to the filing of a post-effective amendment which indicates that all securities offered have been sold or which deregisters all securities then remaining unsold, shall be
deemed to be incorporated by reference herein and to be a part of this registration statement from the date of the filing of such reports and documents. </FONT></P> <P STYLE="margin-top:24px;margin-bottom:0px" ALIGN="center"><FONT
FACE="Times New Roman" SIZE="2"><B>EXHIBITS </B></FONT></P> <P STYLE="font-size:12px;margin-top:0px;margin-bottom:0px">&nbsp;</P>
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<TD VALIGN="bottom" ALIGN="center" STYLE="border-bottom:1px solid #000000"><FONT FACE="Times New Roman" SIZE="1"><B>Exhibit<BR>Number</B></FONT></TD>
<TD VALIGN="bottom"><FONT SIZE="1">&nbsp;</FONT></TD>
<TD VALIGN="bottom"><FONT SIZE="1">&nbsp;</FONT></TD></TR>
<TR>
<TD VALIGN="top"><FONT FACE="Times New Roman" SIZE="2">5.1</FONT></TD>
<TD VALIGN="bottom"><FONT SIZE="1">&nbsp;</FONT></TD>
<TD VALIGN="bottom"><FONT FACE="Times New Roman" SIZE="2">Opinion of Cooley Godward LLP.</FONT></TD></TR>
<TR>
<TD HEIGHT="8"></TD>
<TD HEIGHT="8" COLSPAN="2"></TD></TR>
<TR>
<TD VALIGN="top"><FONT FACE="Times New Roman" SIZE="2">23.1</FONT></TD>
<TD VALIGN="bottom"><FONT SIZE="1">&nbsp;</FONT></TD>
<TD VALIGN="bottom"><FONT FACE="Times New Roman" SIZE="2">Consent of Independent Registered Public Accounting Firm.</FONT></TD></TR>
<TR>
<TD HEIGHT="8"></TD>
<TD HEIGHT="8" COLSPAN="2"></TD></TR>
<TR>
<TD VALIGN="top"><FONT FACE="Times New Roman" SIZE="2">23.2</FONT></TD>
<TD VALIGN="bottom"><FONT SIZE="1">&nbsp;</FONT></TD>
<TD VALIGN="bottom"><FONT FACE="Times New Roman" SIZE="2">Consent of Cooley Godward LLP is contained in Exhibit&nbsp;5.1 to this Registration Statement.</FONT></TD></TR>
<TR>
<TD HEIGHT="8"></TD>
<TD HEIGHT="8" COLSPAN="2"></TD></TR>
<TR>
<TD VALIGN="top"><FONT FACE="Times New Roman" SIZE="2">24.1</FONT></TD>
<TD VALIGN="bottom"><FONT SIZE="1">&nbsp;</FONT></TD>
<TD VALIGN="bottom"><FONT FACE="Times New Roman" SIZE="2">Power of Attorney is contained on the signature pages.</FONT></TD></TR>
</TABLE> <P STYLE="margin-top:0px;margin-bottom:0px"><FONT SIZE="1">&nbsp;</FONT></P>
 <P STYLE="margin-top:0px;margin-bottom:0px" ALIGN="center"><FONT FACE="Times New Roman" SIZE="2">2 </FONT></P>


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 <P STYLE="margin-top:0px;margin-bottom:0px" ALIGN="center"><FONT FACE="Times New Roman" SIZE="2"><B>SIGNATURES </B></FONT></P> <P STYLE="margin-top:12px;margin-bottom:0px"><FONT FACE="Times New Roman"
SIZE="2">Pursuant to the requirements of the Securities Act of 1933, as amended, the Registrant certifies that it has reasonable grounds to believe that it meets all of the requirements for filing on Form&nbsp;S-8 and has duly caused this
Registration Statement to be signed on its behalf by the undersigned, thereunto duly authorized, in the City of Concord, State of California, on August&nbsp;8, 2006. </FONT></P> <P
STYLE="font-size:12px;margin-top:0px;margin-bottom:0px">&nbsp;</P><DIV ALIGN="right">
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<TD WIDTH="7%"></TD>
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<TD WIDTH="92%"></TD></TR>
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<TD VALIGN="top" COLSPAN="3"><FONT FACE="Times New Roman" SIZE="2"><B>CERUS CORPORATION</B></FONT></TD></TR>
<TR>
<TD HEIGHT="16"></TD>
<TD HEIGHT="16" COLSPAN="2"></TD></TR>
<TR>
<TD VALIGN="top"><FONT FACE="Times New Roman" SIZE="2">By:</FONT></TD>
<TD VALIGN="bottom"><FONT SIZE="1">&nbsp;</FONT></TD>
<TD VALIGN="top"> <P STYLE="margin-bottom:1px;border-bottom:1px solid #000000"><FONT FACE="Times New Roman" SIZE="2">/s/ William J. Dawson</FONT></P></TD></TR>
<TR>
<TD VALIGN="top"></TD>
<TD VALIGN="bottom"><FONT SIZE="1">&nbsp;</FONT></TD>
<TD VALIGN="top"><FONT FACE="Times New Roman" SIZE="2">William J. Dawson</FONT></TD></TR>
<TR>
<TD VALIGN="top"></TD>
<TD VALIGN="bottom"><FONT SIZE="1">&nbsp;</FONT></TD>
<TD VALIGN="top"><FONT FACE="Times New Roman" SIZE="2">Title: Vice President, Finance and Chief Financial Officer</FONT></TD></TR>
</TABLE></DIV> <P STYLE="margin-top:18px;margin-bottom:0px"><FONT FACE="Times New Roman" SIZE="2"><B>POWER OF ATTORNEY </B></FONT></P> <P STYLE="margin-top:6px;margin-bottom:0px"><FONT
FACE="Times New Roman" SIZE="2"><B>KNOW ALL PERSONS BY THESE PRESENTS</B>, that each person whose signature appears below constitutes and appoints Claes Glassell and William J. Dawson, and each or any one of them, his or her true and lawful
attorney-in-fact and agent, with full power of substitution and resubstitution, for him or her and in his or her name, place and stead, in any and all capacities, to sign any and all amendments (including post-effective amendments) to this
Registration Statement, and to file the same, with all exhibits thereto, and other documents in connection therewith, with the Securities and Exchange Commission, granting unto said attorneys-in-fact and agents, and each of them, full power and
authority to do and perform each and every act and thing requisite and necessary to be done in connection therewith, as fully to all intents and purposes as he or she might or could do in person, hereby ratifying and confirming all that said
attorneys-in-fact and agents, or any of them, or their or his or her substitutes or substitute, may lawfully do or cause to be done by virtue hereof. </FONT></P> <P STYLE="margin-top:12px;margin-bottom:0px"><FONT FACE="Times New Roman"
SIZE="2">Pursuant to the requirements of the Securities Act of 1933, as amended, this Registration Statement has been signed by the following persons in the capacities and on the dates indicated. </FONT></P> <P
STYLE="font-size:12px;margin-top:0px;margin-bottom:0px">&nbsp;</P>
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<TD WIDTH="43%"></TD>
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<TD WIDTH="15%"></TD></TR>
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<TD VALIGN="top"> <P STYLE="margin-right:0px;margin-top:0px;margin-bottom:1px;border-bottom:1px solid #000000"><FONT FACE="Times New Roman" SIZE="1"><B>Signature</B></FONT></P></TD>
<TD VALIGN="bottom"><FONT SIZE="1">&nbsp;&nbsp;</FONT></TD>
<TD VALIGN="top" STYLE="border-bottom:1px solid #000000"> <P STYLE="margin-top:0px;margin-bottom:1px"><FONT FACE="Times New Roman" SIZE="1"><B>Title</B></FONT></P></TD>
<TD VALIGN="bottom"><FONT SIZE="1">&nbsp;</FONT></TD>
<TD VALIGN="top" STYLE="border-bottom:1px solid #000000"> <P STYLE="margin-top:0px;margin-bottom:1px"><FONT FACE="Times New Roman" SIZE="1"><B>Date</B></FONT></P></TD></TR>
<TR>
<TD VALIGN="top"> <P STYLE="margin-bottom:0px;border-bottom:1px solid #000000"><FONT FACE="Times New Roman" SIZE="2">/s/ Claes Glassell</FONT></P> <P STYLE="margin-top:0px;margin-bottom:1px"><FONT FACE="Times New Roman" SIZE="2">(Claes
Glassell)</FONT></P></TD>
<TD VALIGN="bottom"><FONT SIZE="1">&nbsp;&nbsp;</FONT></TD>
<TD VALIGN="top"><FONT FACE="Times New Roman" SIZE="2">President, Chief Executive Officer and Director (Principal Executive Officer)</FONT></TD>
<TD VALIGN="bottom"><FONT SIZE="1">&nbsp;</FONT></TD>
<TD VALIGN="top" ALIGN="center"><FONT FACE="Times New Roman" SIZE="2">August 8, 2006</FONT></TD></TR>
</TABLE> <P STYLE="margin-top:0px;margin-bottom:0px"><FONT SIZE="1">&nbsp;</FONT></P>
 <P STYLE="margin-top:0px;margin-bottom:0px" ALIGN="center"><FONT FACE="Times New Roman" SIZE="2">3 </FONT></P>


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<TD VALIGN="top"> <P STYLE="margin-bottom:0px;border-bottom:1px solid #000000"><FONT FACE="Times New Roman" SIZE="2">/s/ William J. Dawson</FONT></P> <P STYLE="margin-top:0px;margin-bottom:1px"><FONT FACE="Times New Roman" SIZE="2">(William J.
Dawson)</FONT></P></TD>
<TD VALIGN="bottom"><FONT SIZE="1">&nbsp;&nbsp;</FONT></TD>
<TD VALIGN="top"><FONT FACE="Times New Roman" SIZE="2">Vice President, Finance and Chief Financial Officer (Principal Financial and Accounting Officer)</FONT></TD>
<TD VALIGN="bottom"><FONT SIZE="1">&nbsp;</FONT></TD>
<TD VALIGN="top"><FONT FACE="Times New Roman" SIZE="2">August&nbsp;8, 2006</FONT></TD></TR>
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<TD HEIGHT="16"></TD>
<TD HEIGHT="16" COLSPAN="2"></TD>
<TD HEIGHT="16" COLSPAN="2"></TD></TR>
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<TD VALIGN="top"> <P STYLE="margin-bottom:0px;border-bottom:1px solid #000000"><FONT FACE="Times New Roman" SIZE="2">/s/ Timothy B. Anderson</FONT></P> <P STYLE="margin-top:0px;margin-bottom:1px"><FONT FACE="Times New Roman" SIZE="2">(Timothy B.
Anderson)</FONT></P></TD>
<TD VALIGN="bottom"><FONT SIZE="1">&nbsp;&nbsp;</FONT></TD>
<TD VALIGN="top"><FONT FACE="Times New Roman" SIZE="2">Director</FONT></TD>
<TD VALIGN="bottom"><FONT SIZE="1">&nbsp;</FONT></TD>
<TD VALIGN="top"><FONT FACE="Times New Roman" SIZE="2">August 8, 2006</FONT></TD></TR>
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<TD HEIGHT="16"></TD>
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<TD VALIGN="top"> <P STYLE="margin-bottom:0px;border-bottom:1px solid #000000"><FONT FACE="Times New Roman" SIZE="2">/s/ B. J. Cassin</FONT></P> <P STYLE="margin-top:0px;margin-bottom:1px"><FONT FACE="Times New Roman" SIZE="2">(B. J.
Cassin)</FONT></P></TD>
<TD VALIGN="bottom"><FONT SIZE="1">&nbsp;&nbsp;</FONT></TD>
<TD VALIGN="top"><FONT FACE="Times New Roman" SIZE="2">Director</FONT></TD>
<TD VALIGN="bottom"><FONT SIZE="1">&nbsp;</FONT></TD>
<TD VALIGN="top"><FONT FACE="Times New Roman" SIZE="2">August 8, 2006</FONT></TD></TR>
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<TD HEIGHT="16" COLSPAN="2"></TD>
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<TD VALIGN="top"> <P STYLE="margin-bottom:0px;border-bottom:1px solid #000000"><FONT FACE="Times New Roman" SIZE="2">/s/ Laurence M. Corash</FONT></P> <P STYLE="margin-top:0px;margin-bottom:1px"><FONT FACE="Times New Roman" SIZE="2">(Laurence M.
Corash)</FONT></P></TD>
<TD VALIGN="bottom"><FONT SIZE="1">&nbsp;&nbsp;</FONT></TD>
<TD VALIGN="top"><FONT FACE="Times New Roman" SIZE="2">Director</FONT></TD>
<TD VALIGN="bottom"><FONT SIZE="1">&nbsp;</FONT></TD>
<TD VALIGN="top"><FONT FACE="Times New Roman" SIZE="2">August 8, 2006</FONT></TD></TR>
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<TD HEIGHT="16"></TD>
<TD HEIGHT="16" COLSPAN="2"></TD>
<TD HEIGHT="16" COLSPAN="2"></TD></TR>
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<TD VALIGN="top"> <P STYLE="margin-bottom:0px;border-bottom:1px solid #000000"><FONT FACE="Times New Roman" SIZE="2">/s/ Bruce C. Cozadd</FONT></P> <P STYLE="margin-top:0px;margin-bottom:1px"><FONT FACE="Times New Roman" SIZE="2">(Bruce C.
Cozadd)</FONT></P></TD>
<TD VALIGN="bottom"><FONT SIZE="1">&nbsp;&nbsp;</FONT></TD>
<TD VALIGN="top"><FONT FACE="Times New Roman" SIZE="2">Director</FONT></TD>
<TD VALIGN="bottom"><FONT SIZE="1">&nbsp;</FONT></TD>
<TD VALIGN="top"><FONT FACE="Times New Roman" SIZE="2">August 8, 2006</FONT></TD></TR>
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<TD HEIGHT="16"></TD>
<TD HEIGHT="16" COLSPAN="2"></TD>
<TD HEIGHT="16" COLSPAN="2"></TD></TR>
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<TD VALIGN="top"> <P STYLE="margin-bottom:0px;border-bottom:1px solid #000000"><FONT FACE="Times New Roman" SIZE="2">/s/ William R. Rohn</FONT></P> <P STYLE="margin-top:0px;margin-bottom:1px"><FONT FACE="Times New Roman" SIZE="2">(William R.
Rohn)</FONT></P></TD>
<TD VALIGN="bottom"><FONT SIZE="1">&nbsp;&nbsp;</FONT></TD>
<TD VALIGN="top"><FONT FACE="Times New Roman" SIZE="2">Director</FONT></TD>
<TD VALIGN="bottom"><FONT SIZE="1">&nbsp;</FONT></TD>
<TD VALIGN="top"><FONT FACE="Times New Roman" SIZE="2">August 8, 2006</FONT></TD></TR>
</TABLE> <P STYLE="margin-top:0px;margin-bottom:0px"><FONT SIZE="1">&nbsp;</FONT></P>
 <P STYLE="margin-top:0px;margin-bottom:0px" ALIGN="center"><FONT FACE="Times New Roman" SIZE="2">4 </FONT></P>


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 <P STYLE="margin-top:0px;margin-bottom:0px" ALIGN="center"><FONT FACE="Times New Roman" SIZE="2"><B>EXHIBIT INDEX </B></FONT></P> <P STYLE="font-size:12px;margin-top:0px;margin-bottom:0px">&nbsp;</P>
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<TD VALIGN="bottom" STYLE="border-bottom:1px solid #000000"> <P STYLE="margin-top:0px;margin-bottom:0px"><FONT FACE="Times New Roman" SIZE="1"><B>Exhibit</B></FONT></P> <P STYLE="margin-top:0px;margin-bottom:1px"><FONT FACE="Times New Roman"
SIZE="1"><B>Number</B></FONT></P></TD>
<TD VALIGN="bottom"><FONT SIZE="1">&nbsp;</FONT></TD>
<TD VALIGN="bottom" STYLE="border-bottom:1px solid #000000"> <P STYLE="margin-top:0px;margin-bottom:1px"><FONT FACE="Times New Roman" SIZE="1"><B>Description</B></FONT></P></TD></TR>
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<TD VALIGN="top"><FONT FACE="Times New Roman" SIZE="2">5.1</FONT></TD>
<TD VALIGN="bottom"><FONT SIZE="1">&nbsp;</FONT></TD>
<TD VALIGN="top"> <P STYLE="margin-left:1.00em; text-indent:-1.00em"><FONT FACE="Times New Roman" SIZE="2">Opinion of Cooley Godward LLP.</FONT></P></TD></TR>
<TR>
<TD HEIGHT="8"></TD>
<TD HEIGHT="8" COLSPAN="2"></TD></TR>
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<TD VALIGN="top"><FONT FACE="Times New Roman" SIZE="2">23.1</FONT></TD>
<TD VALIGN="bottom"><FONT SIZE="1">&nbsp;</FONT></TD>
<TD VALIGN="top"> <P STYLE="margin-left:1.00em; text-indent:-1.00em"><FONT FACE="Times New Roman" SIZE="2">Consent of Independent Registered Public Accounting Firm.</FONT></P></TD></TR>
<TR>
<TD HEIGHT="8"></TD>
<TD HEIGHT="8" COLSPAN="2"></TD></TR>
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<TD VALIGN="top"><FONT FACE="Times New Roman" SIZE="2">23.2</FONT></TD>
<TD VALIGN="bottom"><FONT SIZE="1">&nbsp;</FONT></TD>
<TD VALIGN="top"> <P STYLE="margin-left:1.00em; text-indent:-1.00em"><FONT FACE="Times New Roman" SIZE="2">Consent of Cooley Godward LLP is contained in Exhibit&nbsp;5.1 to this Registration Statement.</FONT></P></TD></TR>
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<TD HEIGHT="8" COLSPAN="2"></TD></TR>
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<TD VALIGN="top"><FONT FACE="Times New Roman" SIZE="2">24.1</FONT></TD>
<TD VALIGN="bottom"><FONT SIZE="1">&nbsp;</FONT></TD>
<TD VALIGN="top"> <P STYLE="margin-left:1.00em; text-indent:-1.00em"><FONT FACE="Times New Roman" SIZE="2">Power of Attorney is contained on the signature pages.</FONT></P></TD></TR>
</TABLE> <P STYLE="margin-top:0px;margin-bottom:0px"><FONT SIZE="1">&nbsp;</FONT></P>
 <P STYLE="margin-top:0px;margin-bottom:0px" ALIGN="center"><FONT FACE="Times New Roman" SIZE="2">5 </FONT></P>

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<DOCUMENT>
<TYPE>EX-5.1
<SEQUENCE>2
<FILENAME>dex51.htm
<DESCRIPTION>OPINION OF COOLEY GODWARD LLP
<TEXT>
<HTML><HEAD>
<TITLE>Opinion of Cooley Godward LLP</TITLE>
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 <P STYLE="margin-top:0px;margin-bottom:0px" ALIGN="right"><FONT FACE="Times New Roman" SIZE="2"><B>Exhibit 5.1 </B></FONT></P> <P STYLE="margin-top:6px;margin-bottom:0px" ALIGN="center"><FONT
FACE="Times New Roman" SIZE="2">[Letterhead of Cooley Godward LLP] </FONT></P> <P STYLE="margin-top:12px;margin-bottom:0px; margin-left:2%; text-indent:-2%"><FONT FACE="Times New Roman" SIZE="2">August&nbsp;7, 2006 </FONT></P> <P
STYLE="margin-top:12px;margin-bottom:0px; margin-left:2%; text-indent:-2%"><FONT FACE="Times New Roman" SIZE="2">Cerus Corporation </FONT></P> <P STYLE="margin-top:0px;margin-bottom:0px; margin-left:2%; text-indent:-2%"><FONT FACE="Times New Roman"
SIZE="2">2525 Stanwell Drive, Suite 300 </FONT></P> <P STYLE="margin-top:0px;margin-bottom:0px; margin-left:2%; text-indent:-2%"><FONT FACE="Times New Roman" SIZE="2">Concord, CA 94520 </FONT></P> <P
STYLE="margin-top:18px;margin-bottom:0px; margin-left:2%; text-indent:-2%"><FONT FACE="Times New Roman" SIZE="2">Ladies and Gentlemen: </FONT></P> <P STYLE="margin-top:6px;margin-bottom:0px"><FONT FACE="Times New Roman" SIZE="2">You have requested
our opinion with respect to certain matters in connection with the filing by Cerus Corporation (the &#147;Company&#148;) of a Registration Statement on Form&nbsp;S-8 (the &#147;Registration Statement&#148;) with the Securities and Exchange
Commission covering the offering of up to 800,000 shares of the Company&#146;s Common Stock, $.001 par value per share, (the &#147;Shares&#148;) pursuant to its 1999 Equity Incentive Plan (the &#147;Plan&#148;). </FONT></P> <P
STYLE="margin-top:12px;margin-bottom:0px"><FONT FACE="Times New Roman" SIZE="2">In connection with this opinion, we have examined the Plan, the Registration Statement and related Prospectus, your Certificate of Incorporation and By-laws, as amended
and restated, and such other documents, records, certificates, memoranda and other instruments as we deem necessary as a basis for this opinion. We have assumed the genuineness and authenticity of all documents submitted to us as originals, the
conformity to originals of all documents submitted to us as copies thereof, and the due execution and delivery of all documents where due execution and delivery are a prerequisite to the effectiveness thereof. </FONT></P> <P
STYLE="margin-top:12px;margin-bottom:0px"><FONT FACE="Times New Roman" SIZE="2">On the basis of the foregoing, and in reliance thereon, we are of the opinion that the Shares, when sold and issued in accordance with the Plan, the Registration
Statement and related Prospectus, will be validly issued, fully paid, and nonassessable (except as to shares issued pursuant to certain deferred payment arrangements, which will be fully paid and nonassessable when such deferred payments are made in
full). </FONT></P> <P STYLE="margin-top:12px;margin-bottom:0px; margin-left:2%; text-indent:-2%"><FONT FACE="Times New Roman" SIZE="2">We consent to the filing of this opinion as an exhibit to the Registration Statement. </FONT></P> <P
STYLE="margin-top:12px;margin-bottom:0px; margin-left:2%; text-indent:-2%"><FONT FACE="Times New Roman" SIZE="2">Very truly yours, </FONT></P> <P STYLE="font-size:12px;margin-top:0px;margin-bottom:0px">&nbsp;</P>
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<TD WIDTH="92%"></TD></TR>
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<TD VALIGN="top" COLSPAN="3"><FONT FACE="Times New Roman" SIZE="2">Cooley Godward LLP</FONT></TD></TR>
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<TD HEIGHT="16"></TD>
<TD HEIGHT="16" COLSPAN="2"></TD></TR>
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<TD VALIGN="top"><FONT FACE="Times New Roman" SIZE="2">By:</FONT></TD>
<TD VALIGN="bottom"><FONT SIZE="1">&nbsp;</FONT></TD>
<TD VALIGN="bottom"> <P STYLE="margin-bottom:1px;border-bottom:1px solid #000000"><FONT FACE="Times New Roman" SIZE="2">/s/ Suzanne Sawochka Hooper</FONT></P></TD></TR>
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<TD VALIGN="bottom"><FONT SIZE="1">&nbsp;</FONT></TD>
<TD VALIGN="bottom"><FONT FACE="Times New Roman" SIZE="2">Suzanne Sawochka Hooper</FONT></TD></TR>
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<DOCUMENT>
<TYPE>EX-23.1
<SEQUENCE>3
<FILENAME>dex231.htm
<DESCRIPTION>CONSENT OF INDEPENDENT REGISTERED PUBLIC ACCOUNTING FIRM
<TEXT>
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<TITLE>Consent of Independent Registered Public Accounting Firm</TITLE>
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 <P STYLE="margin-top:0px;margin-bottom:0px" ALIGN="right"><FONT FACE="Times New Roman" SIZE="2"><B>Exhibit 23.1 </B></FONT></P> <P STYLE="margin-top:6px;margin-bottom:0px" ALIGN="center"><FONT
FACE="Times New Roman" SIZE="2"><B>CONSENT OF INDEPENDENT REGISTERED PUBLIC ACCOUNTING FIRM </B></FONT></P> <P STYLE="margin-top:12px;margin-bottom:0px; text-indent:4%"><FONT FACE="Times New Roman" SIZE="2">We consent to the incorporation by
reference in the Registration Statement (Form S-8) pertaining to the 1999 Equity Incentive Plan of Cerus Corporation of our reports dated February&nbsp;22, 2006 with respect to the financial statements of Cerus Corporation, Cerus Corporation&#146;s
management&#146;s assessment of the effectiveness of internal control over financial reporting, and the effectiveness of internal control over financial reporting of Cerus Corporation included in its Annual Report (Form&nbsp;10-K) for the year ended
December&nbsp;31, 2005, filed with the Securities and Exchange Commission. </FONT></P> <P STYLE="margin-top:12px;margin-bottom:0px"><FONT FACE="Times New Roman" SIZE="2">/s/&nbsp;&nbsp;&nbsp;&nbsp;Ernst &amp; Young, LLP </FONT></P> <P
STYLE="margin-top:12px;margin-bottom:0px"><FONT FACE="Times New Roman" SIZE="2">Palo Alto, California </FONT></P> <P STYLE="margin-top:0px;margin-bottom:0px"><FONT FACE="Times New Roman" SIZE="2">August 7, 2006 </FONT></P>
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