FOR IMMEDIATE RELEASE

Reminder: Please Join Us For The F5 Networks Conference Call

NASDAQ: FFIV

TOPIC: F5 First Quarter Financial Results

DATE: Wednesday, January 19, 2011

TIME: 1:30 p.m. Pacific (4:30 p.m. Eastern)

DIAL IN NUMBER: 800-857-3834 (US & Canada) / +1-210-839-8222 (International)

CALL LEADER: John McAdam

PASSCODE: F5 NETWORKS

Please call in 10 minutes ahead of time to ensure a proper connection. We look forward to having you join us. If you have any problems or questions, please call F5 NETWORKS, INC. (206) 272-5555.

REPLAY INFORMATION
Replay Via Phone: Available January 19, 2011 (from 4:30 p.m. Pacific) through January 20, 2011 (until 11:59 p.m. Pacific)

Phone: 800-934-9421 (US & Canada) / + 1-203-369-3391 (International)

Replay Via Internet: http://www.f5.com/about/investor-relations/events-calendar.html - Available until April 20, 2011

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All brands, names, or trademarks mentioned in this document are the property of their respective owners. This press release may contain forward looking statements relating to future events or future financial performance that involve risks and uncertainties. Such statements can be identified by terminology such as "may," "will," "should," "expects," "plans," "anticipates," "believes," "estimates," "predicts", "potential" or "continue" or the negative of such terms or comparable terms. These statements are only predictions and actual results could differ materially from those anticipated in these statements based upon a number of factors including those identified in the Company's filings with the SEC.