<SUBMISSION>
<ACCESSION-NUMBER>0000950134-09-007102
<TYPE>8-K
<PUBLIC-DOCUMENT-COUNT>2
<PERIOD>20090407
<ITEMS>2.02
<ITEMS>9.01
<FILING-DATE>20090407
<DATE-OF-FILING-DATE-CHANGE>20090407
<FILER>
<COMPANY-DATA>
<CONFORMED-NAME>F5 NETWORKS INC
<CIK>0001048695
<ASSIGNED-SIC>3576
<IRS-NUMBER>911714307
<STATE-OF-INCORPORATION>WA
<FISCAL-YEAR-END>0930
</COMPANY-DATA>
<FILING-VALUES>
<FORM-TYPE>8-K
<ACT>34
<FILE-NUMBER>000-26041
<FILM-NUMBER>09737806
</FILING-VALUES>
<BUSINESS-ADDRESS>
<STREET1>401 ELLIOT AVE WEST
<STREET2>STE 500
<CITY>SEATTLE
<STATE>WA
<ZIP>98119
<PHONE>2062725555
</BUSINESS-ADDRESS>
<MAIL-ADDRESS>
<STREET1>401 ELLIOT AVE WEST
<STREET2>STE 500
<CITY>SEATTLE
<STATE>WA
<ZIP>98119
</MAIL-ADDRESS>
<FORMER-COMPANY>
<FORMER-CONFORMED-NAME>F5 LABS INC
<DATE-CHANGED>19990305
</FORMER-COMPANY>
</FILER>
<DOCUMENT>
<TYPE>8-K
<SEQUENCE>1
<FILENAME>v52063e8vk.htm
<DESCRIPTION>FORM 8-K
<TEXT>
<HTML>
<HEAD>
<TITLE>e8vk</TITLE>
</HEAD>
<BODY bgcolor="#FFFFFF">
<!-- PAGEBREAK -->
<DIV style="font-family: 'Times New Roman',Times,serif">


<DIV style="width: 100%; border-bottom: 2pt solid black; font-size: 1pt">&nbsp;</DIV>
<DIV style="width: 100%; border-bottom: 1pt solid black; font-size: 1pt">&nbsp;</DIV>








<DIV align="center" style="font-size: 14pt; margin-top: 12pt"><B>UNITED STATES SECURITIES AND EXCHANGE COMMISSION</B>
</DIV>

<DIV align="center" style="font-size: 12pt"><B>WASHINGTON, D.C. 20549</B>
</DIV>

<DIV align="center" style="font-size: 18pt; margin-top: 12pt"><B>FORM 8-K</B>
</DIV>


<DIV align="center" style="font-size: 12pt; margin-top: 12pt"><B>CURRENT REPORT<BR>
Pursuant to Section&nbsp;13 or 15(d) of the<BR>
Securities Exchange Act of 1934</B></div>
<DIV align="center" style="font-size: 10pt; margin-top: 10pt"><B>Date of Report (Date of Earliest Event Reported):</B>
</DIV>


<DIV align="center" style="font-size: 10pt; margin-top: 0pt"><B>April&nbsp;7, 2009</B>
</DIV>

<DIV align="center" style="font-size: 24pt; margin-top: 12pt"><B>F5 Networks, Inc.</B>
</DIV>

<DIV align="center" style="font-size: 10pt">
(Exact name of registrant as specified in its charter)</DIV>


<DIV align="center">
<TABLE style="font-size: 10pt" cellspacing="0" border="0" cellpadding="0" width="100%">
<!-- Begin Table Head -->
<TR valign="bottom">
    <TD width="30%">&nbsp;</TD>
    <TD width="5%">&nbsp;</TD>
    <TD width="30%">&nbsp;</TD>
    <TD width="5%">&nbsp;</TD>
    <TD width="30%">&nbsp;</TD>
</TR>
<!-- End Table Head -->
<!-- Begin Table Body -->
<TR valign="bottom">
    <TD align="center" valign="top">Washington
</TD>
    <TD>&nbsp;</TD>
    <TD align="center" valign="top">000-26041
</TD>
    <TD>&nbsp;</TD>
    <TD align="center" valign="top">91-1714307</TD>
</TR>
<TR style="font-size: 1px">
    <TD align="center" valign="top" style="border-top: 1px solid #000000">&nbsp;
</TD>
    <TD>&nbsp;</TD>
    <TD align="center" valign="top" style="border-top: 1px solid #000000">&nbsp;
</TD>
    <TD>&nbsp;</TD>
    <TD align="center" valign="top" style="border-top: 1px solid #000000">&nbsp;</TD>
</TR>
<TR valign="bottom">
    <TD align="center" valign="top">(State or other jurisdiction
</TD>
    <TD>&nbsp;</TD>
    <TD align="center" valign="top">(Commission
</TD>
    <TD>&nbsp;</TD>
    <TD align="center" valign="top">(IRS Employer</TD>
</TR>
<TR valign="bottom">
    <TD align="center" valign="top">of incorporation)
</TD>
    <TD>&nbsp;</TD>
    <TD align="center" valign="top">File Number)
</TD>
    <TD>&nbsp;</TD>
    <TD align="center" valign="top">Identification No.)</TD>
</TR>
<!-- End Table Body -->
</TABLE>
</DIV>


<DIV align="center" style="font-size: 10pt; margin-top: 18pt">401 Elliott Avenue West<BR>
Seattle, WA 98119
</DIV>


<DIV align="center" style="font-size: 10pt; margin-top: 0pt">(Address of principal executive offices) (Zip Code)
</DIV>

<DIV align="center" style="font-size: 10pt; margin-top: 12pt">
Registrant&#146;s telephone number, including area code (206)&nbsp;272-5555<BR><BR style="font-size: 6pt">


Not Applicable</DIV>


<DIV align="center" style="font-size: 10pt; margin-top: 0pt">
Former name or former address, if changed since last report</DIV>


<DIV align="left" style="font-size: 10pt; margin-top: 6pt">Check the appropriate box below if the Form 8-K filing is intended to simultaneously satisfy the
filing obligation of the registrant under any of the following provisions:</DIV>

<DIV align="left" style="margin-top: 6pt">
<TABLE width="100%" border="0" cellpadding="0" cellspacing="0" style="font-size: 10pt; background: transparent; color: #000000">
<TR>
    <TD width="1%"></TD>
    <TD width="1%"></TD>
    <TD></TD>
</TR>

<TR>
    <TD><FONT face="Wingdings">&#111;</FONT></TD>
    <TD>&nbsp;</TD>
    <TD>Written communications pursuant to Rule&nbsp;425 under the Securities Act (17 CFR 230.425)
</TD>
</TR>
</TABLE>
</DIV>

<DIV align="left" style="margin-top: 6pt">
<TABLE width="100%" border="0" cellpadding="0" cellspacing="0" style="font-size: 10pt; background: transparent; color: #000000">
<TR>
    <TD width="1%"></TD>
    <TD width="1%"></TD>
    <TD></TD>
</TR>

<TR>
    <TD><FONT face="Wingdings">&#111;</FONT></TD>
    <TD>&nbsp;</TD>
    <TD>Soliciting material pursuant to Rule&nbsp;14a-12 under the Exchange Act (17 CFR 240.14a-12)
</TD>
</TR>
</TABLE>
</DIV>

<DIV align="left" style="margin-top: 6pt">
<TABLE width="100%" border="0" cellpadding="0" cellspacing="0" style="font-size: 10pt; background: transparent; color: #000000">
<TR>
    <TD width="1%"></TD>
    <TD width="1%"></TD>
    <TD></TD>
</TR>

<TR>
    <TD><FONT face="Wingdings">&#111;</FONT></TD>
    <TD>&nbsp;</TD>
    <TD>Pre-commencement communications pursuant to Rule&nbsp;14d-2(b) under the Exchange Act (17 CFR 240.14d-2(b))
</TD>
</TR>
</TABLE>
</DIV>

<DIV align="left" style="margin-top: 6pt">
<TABLE width="100%" border="0" cellpadding="0" cellspacing="0" style="font-size: 10pt; background: transparent; color: #000000">
<TR>
    <TD width="1%"></TD>
    <TD width="1%"></TD>
    <TD></TD>
</TR>

<TR>
    <TD><FONT face="Wingdings">&#111;</FONT></TD>
    <TD>&nbsp;</TD>
    <TD>Pre-commencement communications pursuant to Rule&nbsp;13e-4(c) under the Exchange Act (17 CFR 240.13e-4(c))
</TD>
</TR>
</TABLE>
</DIV>


<DIV style="width: 100%; border-bottom: 1pt solid black; margin-top: 10pt; font-size: 1pt">&nbsp;</DIV>
<DIV style="width: 100%; border-bottom: 2pt solid black; font-size: 1pt">&nbsp;</DIV>











<P align="center" style="font-size: 10pt"><!-- Folio -->&nbsp;<!-- /Folio -->
</DIV>

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<P><HR noshade><P>
<H5 align="left" style="page-break-before:always">&nbsp;</H5><P>

<DIV style="font-family: 'Times New Roman',Times,serif">

<!--TOC-->
<!--/TOC-->






<!-- link1 "Item&nbsp;2.02 Results of Operations and Financial Condition" -->

<DIV align="left" style="margin-top: 12pt">
<TABLE width="100%" border="0" cellpadding="0" cellspacing="0" style="font-size: 10pt; background: transparent; color: #000000">
<TR>
    <TD width="3%"></TD>
    <TD width="1%"></TD>
    <TD></TD>
</TR>
<TR valign="top">
    <TD nowrap align="left"><B>Item&nbsp;2.02</B></TD>
    <TD>&nbsp;</TD>
    <TD><B>Results of Operations and Financial Condition</B></TD>
</TR>
</TABLE>
</DIV>
<DIV align="left" style="font-size: 10pt; margin-top: 6pt">On April&nbsp;7, 2009, F5 Networks, Inc. (the &#147;Company&#148;) issued a press release announcing its
preliminary financial results for the three month period ended March&nbsp;31, 2009, and certain other
information. A copy of the press release is attached as Exhibit&nbsp;99.1 to this report.</DIV>

<DIV align="left" style="font-size: 10pt; margin-top: 6pt">The information furnished pursuant to this Item&nbsp;2.02 and the exhibit hereto shall not be deemed
&#147;filed&#148; for purposes of Section&nbsp;18 of the Securities Exchange Act of 1934, as amended (the
&#147;Exchange Act&#148;), and shall not be deemed to be incorporated by reference in any filing under the
Securities Act of 1933, as amended, or the Exchange Act except as shall be expressly set forth by
specific reference in such filing.</DIV>

<!-- link1 "Item&nbsp;9.01 Financial Statements and Exhibits" -->

<DIV align="left" style="margin-top: 12pt">
<TABLE width="100%" border="0" cellpadding="0" cellspacing="0" style="font-size: 10pt; background: transparent; color: #000000">
<TR>
    <TD width="3%"></TD>
    <TD width="1%"></TD>
    <TD></TD>
</TR>
<TR valign="top">
    <TD nowrap align="left"><B>Item&nbsp;9.01</B></TD>
    <TD>&nbsp;</TD>
    <TD><B>Financial Statements and Exhibits</B></TD>
</TR>
</TABLE>
</DIV>
<DIV align="left" style="font-size: 10pt; margin-top: 6pt">(d)&nbsp;Exhibits:</DIV>

<DIV align="center">
<TABLE style="font-size: 10pt" cellspacing="0" border="0" cellpadding="0" width="100%">
<!-- Begin Table Head -->
<TR valign="bottom">
    <TD width="5%">&nbsp;</TD>
    <TD width="2%">&nbsp;</TD>
    <TD width="90%">&nbsp;</TD>
</TR>
<!-- End Table Head -->
<!-- Begin Table Body -->
<TR valign="bottom">
    <TD valign="top"><DIV style="margin-left:0px; text-indent:-0px">99.1
</DIV></TD>
    <TD>&nbsp;</TD>
    <TD align="left" valign="top">Press Release of F5 Networks, Inc. announcing preliminary financial results dated April&nbsp;7, 2009.</TD>
</TR>
<!-- End Table Body -->
</TABLE>
</DIV>


<P align="center" style="font-size: 10pt"><!-- Folio -->&nbsp;<!-- /Folio -->
</DIV>

<!-- PAGEBREAK -->
<P><HR noshade><P>
<H5 align="left" style="page-break-before:always">&nbsp;</H5><P>

<DIV style="font-family: 'Times New Roman',Times,serif">
<!-- link1 "SIGNATURES" -->

<DIV align="center" style="font-size: 10pt; margin-top: 18pt"><B>SIGNATURES</B>
</DIV>

<DIV align="left" style="font-size: 10pt; margin-top: 6pt">Pursuant to the requirements of the Securities Exchange Act of 1934, the registrant has duly caused
this report to be signed on its behalf by the undersigned hereunto duly authorized.</DIV>


<TABLE width="100%" border="0" cellspacing="0" cellpadding="0" style="font-size: 10pt">
<TR>
    <TD width="48%">&nbsp;</TD>
    <TD width="1%">&nbsp;</TD>
    <TD width="1%">&nbsp;</TD>
    <TD width="35%">&nbsp;</TD>
    <TD width="15%">&nbsp;</TD>
</TR>
<TR>
    <TD valign="top" align="left">&nbsp;</TD>
    <TD colspan="3" align="left">F5 NETWORKS, INC.<BR>
(Registrant)<BR>
&nbsp;</TD>
    <TD>&nbsp;</TD>
</TR><TR>
    <TD align="left">Date: April 7, 2009&nbsp;</TD>
    <TD valign="top">By:&nbsp;&nbsp;</TD>
    <TD colspan="2" style="border-bottom: 1px solid #000000" align="left"><I>/s/ John McAdam</I>
&nbsp;</TD>
    <TD>&nbsp;</TD>
</TR><TR>
    <TD align="left">&nbsp;</TD>
    <TD>&nbsp;</TD>
    <TD colspan="2" align="left">John McAdam&nbsp;</TD>
    <TD>&nbsp;</TD>
</TR><TR>
    <TD align="left">&nbsp;</TD>
    <TD>&nbsp;</TD>
    <TD colspan="2" align="left">President and Chief Executive Officer&nbsp;</TD>
    <TD>&nbsp;</TD>
</TR>
<TR>
    <TD colspan="5">&nbsp;</TD>
</TR>
</TABLE>


<P align="center" style="font-size: 10pt"><!-- Folio -->&nbsp;<!-- /Folio -->
</DIV>

<!-- PAGEBREAK -->
<P><HR noshade><P>
<H5 align="left" style="page-break-before:always">&nbsp;</H5><P>

<DIV style="font-family: 'Times New Roman',Times,serif">
<!-- link1 "EXHIBIT INDEX" -->

<DIV align="center" style="font-size: 10pt; margin-top: 18pt"><B>EXHIBIT INDEX</B>
</DIV>

<DIV align="center">
<TABLE style="font-size: 10pt" cellspacing="0" border="0" cellpadding="0" width="100%">
<!-- Begin Table Head -->
<TR valign="bottom">
    <TD width="8%">&nbsp;</TD>
    <TD width="6%">&nbsp;</TD>
    <TD width="86%">&nbsp;</TD>
</TR>
<TR style="font-size: 8pt" valign="bottom">
    <TD nowrap align="left" style="border-bottom: 1px solid #000000">Exhibit No.</TD>
    <TD>&nbsp;</TD>
    <TD nowrap align="left" style="border-bottom: 1px solid #000000">Description</TD>
</TR>

<!-- End Table Head -->
<!-- Begin Table Body -->
<TR valign="bottom">
    <TD valign="top"><DIV style="margin-left:0px; text-indent:-0px">99.1
</DIV></TD>
    <TD>&nbsp;</TD>
    <TD align="left" valign="top">Press Release of F5 Networks, Inc. announcing preliminary financial results dated April&nbsp;7, 2009.</TD>
</TR>
<!-- End Table Body -->
</TABLE>
</DIV>



<P align="center" style="font-size: 10pt"><!-- Folio -->&nbsp;<!-- /Folio -->
</DIV>



</BODY>
</HTML>
</TEXT>
</DOCUMENT>
<DOCUMENT>
<TYPE>EX-99.1
<SEQUENCE>2
<FILENAME>v52063exv99w1.htm
<DESCRIPTION>EX-99.1
<TEXT>
<HTML>
<HEAD>
<TITLE>exv99w1</TITLE>
</HEAD>
<BODY bgcolor="#FFFFFF">
<!-- PAGEBREAK -->

<DIV style="font-family: 'Times New Roman',Times,serif">


<DIV align="right" style="font-size: 10pt; margin-top: 12pt"><B>Exhibit&nbsp;99.1</B>
</DIV>


<DIV align="left" style="font-size: 10pt; margin-top: 12pt"><B>FOR IMMEDIATE RELEASE</B>
</DIV>

<DIV align="center">
<TABLE style="font-size: 10pt" cellspacing="0" border="0" cellpadding="0" width="100%">
<!-- Begin Table Head -->
<TR valign="bottom">
    <TD width="12%">&nbsp;</TD>
    <TD width="3%">&nbsp;</TD>
    <TD width="85%">&nbsp;</TD>
</TR>
<!-- End Table Head -->
<!-- Begin Table Body -->
<TR valign="bottom">
    <TD valign="top"><DIV style="margin-left:0px; text-indent:-0px"><B>CONTACT:</B>
</DIV></TD>
    <TD>&nbsp;</TD>
    <TD align="left" valign="top">Investor Relations<br>
John Eldridge<br>
(206)&nbsp;272-6571<br>
<u>j.eldridge@f5.com</u></TD>
</TR>
<TR valign="bottom"><!-- Blank Space -->
    <TD valign="top"><DIV style="margin-left:0px; text-indent:-0px">&nbsp;</DIV></TD>
    <TD>&nbsp;</TD>
    <TD align="left" valign="top">&nbsp;</TD>
</TR>
<TR valign="bottom">
    <TD valign="top"><DIV style="margin-left:0px; text-indent:-0px">&nbsp;
</DIV></TD>
    <TD>&nbsp;</TD>
    <TD align="left" valign="top">Public Relations<br>
Alane Moran<br>
(206)&nbsp;272-6850<br>
<u>a.moran@f5.com</u></TD>
</TR>
<!-- End Table Body -->
</TABLE>
</DIV>


<DIV align="center" style="font-size: 10pt; margin-top: 10pt"><B>F5 Networks Announces Preliminary Results for Second Quarter of Fiscal 2009</B>
</DIV>


<DIV align="left" style="font-size: 10pt; margin-top: 6pt"><B>SEATTLE, WA&#151;April&nbsp;7, 2009</B>&#151;F5 Networks, Inc. (NASDAQ: FFIV) today announced preliminary results
for the second quarter of fiscal 2009, ended March&nbsp;31. Revenue for the quarter is expected to be
$154.1&nbsp;million, below the company&#146;s guidance of $157&nbsp;million &#151; $164&nbsp;million. GAAP EPS is expected
to be $0.23 to $0.24 per diluted share, exceeding the company&#146;s guidance of $0.19 &#151; $0.21 per
diluted share. Non-GAAP EPS is expected to be $0.37 to $0.38 per diluted share, within the
company&#146;s guided range of $0.36 to $0.38 per diluted share.
</DIV>

<DIV align="left" style="font-size: 10pt; margin-top: 6pt">According to John McAdam, F5 president and chief executive officer, sales during the second quarter
were slower than expected across all geographic regions. Revenue from the company&#146;s application
delivery controller business was flat compared with the second quarter of last year but down
sequentially from the first quarter of fiscal 2009. Revenue from the company&#146;s file virtualization
business was down year over year but grew approximately 23&nbsp;percent sequentially from the first
quarter of fiscal 2009.
</DIV>

<DIV align="left" style="font-size: 10pt; margin-top: 6pt">Despite the slowdown in overall sales, the company expects to meet its non-GAAP gross margin
targets for the quarter. However, as a result of an accrual for a legal settlement, the company
expects its GAAP gross margin to be slightly below management&#146;s guided range of 77-78%. As a
result of aggressive cost-reduction and expense-control measures, the company expects to achieve a
non-GAAP operating margin above 27% for the quarter, exceeding its target of 25%.
</DIV>

<DIV align="left" style="font-size: 10pt; margin-top: 6pt">Cash flow
from operations is expected to be $39&nbsp;million, above the company&#146;s guidance of $35&nbsp;million, and after
purchasing $27.4&nbsp;million of F5 common stock the company ended the quarter with cash and investments
of approximately $499&nbsp;million.
</DIV>

<P align="center" style="font-size: 10pt"><!-- Folio -->&nbsp;<!-- /Folio -->
</DIV>

<!-- PAGEBREAK -->
<P><HR noshade><P>
<H5 align="left" style="page-break-before:always">&nbsp;</H5><P>

<DIV style="font-family: 'Times New Roman',Times,serif">


<DIV align="center">
<TABLE style="font-size: 10pt" cellspacing="0" border="0" cellpadding="0" width="100%">
<!-- Begin Table Head -->
<TR valign="bottom">
    <TD width="76%">&nbsp;</TD>
    <TD width="5%">&nbsp;</TD>
    <TD width="1%">&nbsp;</TD>
    <TD width="5%">&nbsp;</TD>
    <TD width="1%">&nbsp;</TD>
    <TD width="5%">&nbsp;</TD>
    <TD width="1%">&nbsp;</TD>
    <TD width="5%">&nbsp;</TD>
    <TD width="1%">&nbsp;</TD>
</TR>
<TR style="font-size: 8pt" valign="bottom">
    <TD>&nbsp;</TD>
    <TD>&nbsp;</TD>
    <TD nowrap align="center" colspan="6"><B>Three months ended</B></TD>
    <TD>&nbsp;</TD>
</TR>
<TR style="font-size: 8pt" valign="bottom">
    <TD>&nbsp;</TD>
    <TD>&nbsp;</TD>
    <TD nowrap align="center" colspan="6"><B>March 31, 2009</B></TD>
    <TD>&nbsp;</TD>
</TR>
<TR style="font-size: 8pt" valign="bottom">
    <TD>&nbsp;</TD>
    <TD>&nbsp;</TD>
    <TD nowrap align="center" colspan="6" style="border-bottom: 1px solid #ffffff"><B>(Anticipated)</B></TD>
    <TD>&nbsp;</TD>
</TR>
<TR style="font-size: 8pt" valign="bottom">
    <TD nowrap align="left"><B>Reconciliation of Expected Non-GAAP Second Quarter Earnings</B></TD>
    <TD>&nbsp;</TD>
    <TD nowrap align="center" colspan="2"><B>Low</B></TD>
    <TD>&nbsp;</TD>
    <TD>&nbsp;</TD>
    <TD nowrap align="center" colspan="2"><B>High</B></TD>
    <TD>&nbsp;</TD>
</TR>

<!-- End Table Head -->
<!-- Begin Table Body -->
<TR valign="bottom" style="background: #cceeff">
    <TD><DIV style="margin-left:15px; text-indent:-15px">Net income</DIV></TD>
    <TD>&nbsp;</TD>
    <TD align="left">$</TD>
    <TD align="right">18.5</TD>
    <TD>&nbsp;</TD>
    <TD>&nbsp;</TD>
    <TD align="left">$</TD>
    <TD align="right">19.3</TD>
    <TD>&nbsp;</TD>
</TR>
<TR valign="bottom">
    <TD><DIV style="margin-left:15px; text-indent:-15px">Stock-based compensation expense, net of tax</DIV></TD>
    <TD>&nbsp;</TD>
    <TD align="left">$</TD>
    <TD align="right">7.4</TD>
    <TD>&nbsp;</TD>
    <TD>&nbsp;</TD>
    <TD align="left">$</TD>
    <TD align="right">7.4</TD>
    <TD>&nbsp;</TD>
</TR>
<TR valign="bottom" style="background: #cceeff">
    <TD><DIV style="margin-left:15px; text-indent:-15px">Restructuring charge, net of tax</DIV></TD>
    <TD>&nbsp;</TD>
    <TD align="left">$</TD>
    <TD align="right">3.0</TD>
    <TD>&nbsp;</TD>
    <TD>&nbsp;</TD>
    <TD align="left">$</TD>
    <TD align="right">3.0</TD>
    <TD>&nbsp;</TD>
</TR>
<TR valign="bottom">
    <TD><DIV style="margin-left:15px; text-indent:-15px">Legal settlement, net of tax</DIV></TD>
    <TD>&nbsp;</TD>
    <TD align="left">$</TD>
    <TD align="right">0.9</TD>
    <TD>&nbsp;</TD>
    <TD>&nbsp;</TD>
    <TD align="left">$</TD>
    <TD align="right">0.9</TD>
    <TD>&nbsp;</TD>
</TR>
<TR style="font-size: 1px">
    <TD><DIV style="margin-left:15px; text-indent:-15px">&nbsp;</DIV></TD>
    <TD>&nbsp;</TD>
    <TD nowrap colspan="2" align="right" style="border-top: 1px solid #000000">&nbsp;</TD>
    <TD>&nbsp;</TD>
    <TD>&nbsp;</TD>
    <TD nowrap colspan="2" align="right" style="border-top: 1px solid #000000">&nbsp;</TD>
    <TD>&nbsp;</TD>
</TR>
<TR valign="bottom"><!-- Blank Space -->
    <TD><DIV style="margin-left:15px; text-indent:-15px">&nbsp;</DIV></TD>
    <TD>&nbsp;</TD>
    <TD>&nbsp;</TD>
    <TD>&nbsp;</TD>
    <TD>&nbsp;</TD>
    <TD>&nbsp;</TD>
    <TD>&nbsp;</TD>
    <TD>&nbsp;</TD>
    <TD>&nbsp;</TD>
</TR>
<TR valign="bottom" style="background: #cceeff">
    <TD><DIV style="margin-left:15px; text-indent:-15px">Non-GAAP net income excluding stock-based compensation expense,
restructuring charge and legal settlement</DIV></TD>
    <TD>&nbsp;</TD>
    <TD align="left">$</TD>
    <TD align="right">29.8</TD>
    <TD>&nbsp;</TD>
    <TD>&nbsp;</TD>
    <TD align="left">$</TD>
    <TD align="right">30.6</TD>
    <TD>&nbsp;</TD>
</TR>
<TR style="font-size: 1px">
    <TD><DIV style="margin-left:15px; text-indent:-15px">&nbsp;</DIV></TD>
    <TD>&nbsp;</TD>
    <TD nowrap colspan="2" align="right" style="border-top: 3px double #000000">&nbsp;</TD>
    <TD>&nbsp;</TD>
    <TD>&nbsp;</TD>
    <TD nowrap colspan="2" align="right" style="border-top: 3px double #000000">&nbsp;</TD>
    <TD>&nbsp;</TD>
</TR>
<TR valign="bottom"><!-- Blank Space -->
    <TD><DIV style="margin-left:15px; text-indent:-15px">&nbsp;</DIV></TD>
    <TD>&nbsp;</TD>
    <TD>&nbsp;</TD>
    <TD>&nbsp;</TD>
    <TD>&nbsp;</TD>
    <TD>&nbsp;</TD>
    <TD>&nbsp;</TD>
    <TD>&nbsp;</TD>
    <TD>&nbsp;</TD>
</TR>
<TR valign="bottom">
    <TD><DIV style="margin-left:15px; text-indent:-15px">Net income per share &#151; diluted</DIV></TD>
    <TD>&nbsp;</TD>
    <TD align="left">$</TD>
    <TD align="right">0.23</TD>
    <TD>&nbsp;</TD>
    <TD>&nbsp;</TD>
    <TD align="left">$</TD>
    <TD align="right">0.24</TD>
    <TD>&nbsp;</TD>
</TR>
<TR valign="bottom" style="background: #cceeff">
    <TD><DIV style="margin-left:15px; text-indent:-15px">Non-GAAP net income per share &#151; diluted</DIV></TD>
    <TD>&nbsp;</TD>
    <TD align="left">$</TD>
    <TD align="right">0.37</TD>
    <TD>&nbsp;</TD>
    <TD>&nbsp;</TD>
    <TD align="left">$</TD>
    <TD align="right">0.38</TD>
    <TD>&nbsp;</TD>
</TR>
<!-- End Table Body -->
</TABLE>
</DIV>


<DIV align="left" style="font-size: 10pt; margin-top: 12pt"><B>Conference Call Today</B>
</DIV>


<DIV align="left" style="font-size: 10pt; margin-top: 6pt">F5 will host a conference call today at 2:00 p.m. Pacific (5:00 p.m. Eastern) to discuss its
preliminary second quarter results.
</DIV>
<DIV align="left" style="font-size: 10pt; margin-top: 6pt">DIAL-IN
NUMBERS: 800-857-3834&nbsp;(US &#038; Canada); 1-210-839-8222 (International)
</DIV>


<DIV align="left" style="font-size: 10pt; margin-top: 6pt">CALL LEADER: John McAdam

</DIV>

<DIV align="left" style="font-size: 10pt; margin-top: 6pt">PASSCODE: F5 NETWORKS

</DIV>

<DIV align="left" style="font-size: 10pt; margin-top: 6pt">Please call in 10 minutes ahead of time to ensure a proper connection. If you have any problems or
questions, please call F5 NETWORKS, INC. (206)&nbsp;272-5555.
</DIV>

<DIV align="left" style="font-size: 10pt; margin-top: 6pt">To listen to the live webcast, go to
http://www.f5.com/about/investor-relations/events-calendar.html and click on the webcast URL for
today&#146;s call.
</DIV>

<DIV align="left" style="font-size: 10pt; margin-top: 12pt"><B>Conference Call Replays</B>
</DIV>


<DIV align="left" style="font-size: 10pt; margin-top: 6pt">TELEPHONE
REPLAY: Available from 4:00 p.m. Pacific, April&nbsp;7, 2009, until
11:59 p.m. Pacific, April
8, 2009.
</DIV>

<DIV align="left" style="font-size: 10pt; margin-top: 6pt">DIAL-IN
NUMBERS: 800-839-1174 (US &#038; Canada); 1-203-369-3029  (International)
</DIV>

<DIV align="left" style="font-size: 10pt; margin-top: 6pt">INTERNET REPLAY: Available until April&nbsp;22, 2009
</DIV>

<DIV align="left" style="font-size: 10pt; margin-top: 6pt">http://www.f5.com/about/investor-relations/events-calendar.html
</DIV>

<DIV align="left" style="font-size: 10pt; margin-top: 6pt">The company will report final results for the second quarter of fiscal 2009 in its regularly
scheduled earnings release and conference call on Wednesday, April&nbsp;22, 2009. Call-in numbers and
webcast information are available at
http://www.f5.com/about/investor-relations/events-calendar.html.
</DIV>

<DIV align="left" style="font-size: 10pt; margin-top: 6pt"><B>About F5 Networks</B>

</DIV>

<P align="center" style="font-size: 10pt"><!-- Folio -->&nbsp;<!-- /Folio -->
</DIV>

<!-- PAGEBREAK -->
<P><HR noshade><P>
<H5 align="left" style="page-break-before:always">&nbsp;</H5><P>

<DIV style="font-family: 'Times New Roman',Times,serif">

<DIV align="left" style="font-size: 10pt; margin-top: 6pt">F5 Networks is the global leader in Application Delivery Networking. F5 provides solutions that
make applications secure, fast, and available for everyone. By adding intelligence and
manageability into the network to offload applications and optimize the data storage layer, F5
extends the power of intelligent networking to all levels of application delivery. F5&#146;s extensible
architecture optimizes applications, delivers application reliability and protects the application
and network. Enterprise organizations, service providers and Web 2.0 content providers worldwide
trust F5 to keep their applications running. The company is headquartered in Seattle, Washington
with offices worldwide. For more information, go to www.f5.com.
</DIV>

<DIV align="left" style="font-size: 10pt; margin-top: 12pt"><B>Forward Looking Statements</B>
</DIV>


<DIV align="left" style="font-size: 10pt; margin-top: 6pt">Statements in this press release concerning the continuing strength of F5&#146;s business, sequential
growth, the target revenue and earnings range, share amount and share price assumptions, demand for
application delivery networking and storage virtualization products and other statements that are
not historical facts are forward-looking statements. Such forward-looking statements involve risks
and uncertainties, as well as assumptions and other factors that, if they do not fully materialize
or prove correct, could cause the actual results, performance or achievements of the company, or
industry results, to be materially different from any future results, performance or achievements
expressed or implied by such forward-looking statements. Such factors include, but are not limited
to: customer acceptance of our new traffic management, security, application delivery, WAN
optimization and storage virtualization offerings; the timely development, introduction and
acceptance of additional new products and features by F5 or its competitors; competitive pricing
pressures; increased sales discounts; F5&#146;s ability to sustain, develop and effectively utilize
distribution relationships; F5&#146;s ability to attract, train and retain qualified product
development, marketing, sales, professional services and customer support personnel; F5&#146;s ability
to expand in international markets; the unpredictability of F5&#146;s sales cycle; the share repurchase
program; future prices of F5&#146;s common stock; and other risks and uncertainties described more fully
in our documents filed with or furnished to the Securities and Exchange Commission. All
forward-looking statements in this press release are based on information available as of the date
hereof and qualified in their entirety by this cautionary statement. F5 assumes no obligation to
revise or update these forward-looking statements.
</DIV>

<DIV align="left" style="font-size: 10pt; margin-top: 12pt"><B>GAAP to non-GAAP Reconciliation</B>
</DIV>


<DIV align="left" style="font-size: 10pt; margin-top: 6pt">F5&#146;s management evaluates and makes operating decisions using various operating measures. These
measures are generally based on the revenues of its products, services operations and certain costs
of those operations, such as cost of revenues, research and development, sales and marketing and
general and administrative expenses. One such measure is net income excluding stock-based
compensation, which is a non-GAAP financial measure under Section&nbsp;101 of Regulation&nbsp;G under the
Securities Exchange Act of 1934, as amended. This measure
</DIV>

<P align="center" style="font-size: 10pt"><!-- Folio -->&nbsp;<!-- /Folio -->
</DIV>

<!-- PAGEBREAK -->
<P><HR noshade><P>
<H5 align="left" style="page-break-before:always">&nbsp;</H5><P>

<DIV style="font-family: 'Times New Roman',Times,serif">



<DIV align="left" style="font-size: 10pt; margin-top: 6pt">consists of GAAP net income excluding, as applicable, stock-based compensation. Net income
excluding stock-based compensation (non-GAAP) is adjusted by the amount of additional taxes or tax
benefit that the company would accrue if it used non-GAAP results instead of GAAP results to
calculate the company&#146;s tax liability. Stock-based compensation is a non-cash expense that F5 has
accounted for since July&nbsp;1, 2005 in accordance with the fair value recognition provisions of
Statement of Financial Accounting Standards No.&nbsp;123(R), &#147;Share-Based Payment.&#148;
</DIV>

<DIV align="left" style="font-size: 10pt; margin-top: 6pt">Management believes that net income excluding stock-based compensation (non-GAAP) provides useful
supplemental information to management and investors regarding the performance of the company&#146;s
business operations and facilitates comparisons to the company&#146;s historical operating results.
Although F5&#146;s management finds this non-GAAP measure to be useful in evaluating the performance of
the business, management&#146;s reliance on this measure is limited because items excluded from such
measures could have a material effect on F5&#146;s earnings and earnings per share calculated in
accordance with GAAP. Therefore, F5&#146;s management will use its non-GAAP earnings and earnings per
share measures, in conjunction with GAAP earnings and earnings per share measures, to address these
limitations when evaluating the performance of the company&#146;s business. Investors should consider
these non-GAAP measures in addition to, and not as a substitute for, financial performance measures
in accordance with GAAP.
</DIV>

<DIV align="left" style="font-size: 10pt; margin-top: 6pt">The reconciliation of the company&#146;s GAAP and non-GAAP second quarter earnings also excludes a
restructuring charge related to a loss on facility exit and workforce reduction and a legal
settlement. This restructuring charge was incurred during the second quarter in connection with a
reduction in the company&#146;s workforce and the consolidation of certain of the company&#146;s office
space.
</DIV>

<DIV align="left" style="font-size: 10pt; margin-top: 6pt">F5 believes that presenting its non-GAAP measure of earnings and earnings per share provides
investors with an additional tool for evaluating the performance of the company&#146;s business, which
management uses in its own evaluation of the company&#146;s performance. Investors are encouraged to
look at GAAP results as the best measure of financial performance. For example, stock-based
compensation is an obligation of the Company that should be considered and each line item is
important to financial performance generally. However, while the GAAP results are more complete,
the company provides investors this supplemental measure since, with reconciliation to GAAP, it may
provide additional insight into its operational performance and financial results.
</DIV>

<DIV align="center" style="font-size: 10pt; margin-top: 10pt"># # #
</DIV>


<DIV align="left" style="font-size: 10pt; margin-top: 12pt"><B>Press Contact</B>
</DIV>


<DIV align="left" style="font-size: 10pt; margin-top: 6pt">John Eldridge<BR>
Investor Relations<BR>
F5 Networks, Inc<BR>
(206)&nbsp;272-6571<BR>
<u>j.eldridge@f5.com</u>

</DIV>

<DIV align="left" style="font-size: 10pt; margin-top: 6pt">Alane Moran<BR>
Public Relations<BR>
F5 Networks, Inc<BR>
(206)&nbsp;272-6850<BR>
<u>a.moran@f5.com</u>

</DIV>


<P align="center" style="font-size: 10pt"><!-- Folio -->&nbsp;<!-- /Folio -->
</DIV>



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