TEL AVIV, Israel, June 11 /PRNewswire/ --     Zohar Zisapel announced today that he is extending the
expiration date of his pending tender offer to purchase 5.0% of the
outstanding ordinary shares of RADVISION Ltd. (Nasdaq: RVSN) (currently,
971,394 RADVISION shares) for $7.70 per share, net to the seller in cash,
less any required withholding taxes and without interest.

As a result of the extension, the initial period of the tender
offer and withdrawal rights, previously scheduled to expire on Monday, June
15, 2009, will now expire at 10:00 a.m., New York time, or 5:00 p.m., Israel
time, on Thursday, June 25, 2009. The additional period of the tender offer,
if the conditions to the offer have been satisfied (or waived, to the extent
permitted by applicable law), will now expire at 10:00 a.m., New York time,
or 5:00 p.m., Israel time, on Monday, June 29, 2009. Mr. Zisapel further
announced that he has waived his right to extend the initial offer period
beyond June 25, 2009.

No changes were made to the offer price of $7.70 per share.

According to a preliminary count by the depositaries for the
offer, as of 5:00 p.m., Israel time, on June 10, 2009, 2,728 RADVISION shares
had been validly tendered in Mr. Zisapel's offer and not withdrawn.

On June 10, 2009, the last trading day on Nasdaq before this
announcement, the closing price of the RADVISION shares on Nasdaq was $7.87.
On June 10, 2009, the last full trading day on the Tel Aviv Stock Exchange
(the "TASE") before this announcement, the closing price of the RADVISION
shares on the TASE was NIS 31.72 ($8.10 based on an exchange rate of NIS
3.914 per United States dollar as of June 10, 2009). Mr. Zisapel's offer
price is 2.2% less than the closing price of RADVISION shares on Nasdaq on
June 10, 2009.

The complete terms and conditions of the tender offer, including
important U.S. and Israeli income and withholding tax considerations relating
to the tender offer, are contained in the Offer to Purchase (as amended)
included as an exhibit to the Tender Offer Statement on Schedule TO (as
amended) previously filed (or, with respect to this amendment, to be filed)
with the U.S. Securities and Exchange Commission (SEC) and with the Israeli
Securities Authority (ISA). American Stock Transfer & Trust Company is the
U.S. Depositary for the offer and Clal Finance Batucha Investment Management
Ltd. is the Israeli Depositary for the offer.

Important Information: This is not an offer to buy or the solicitation of
an offer to sell any RADVISION shares. The tender offer that is described in
this press release is only being made through the Offer to Purchase, Letter
of Transmittal and related tender offer documents, as amended. All holders of
RADVISION shares should read the tender offer materials, as amended, and the
Tender Offer Solicitation/Recommendation Statement with respect to the tender
offer filed by RADVISION, with the SEC and the ISA. Holders of RADVISION
shares should read the tender offer materials and the
Solicitation/Recommendation Statement because they contain important
information about the tender offer. The tender offer materials, the
Solicitation/Recommendation Statement and other filed documents are available
at no charge on the SEC's website at http://www.sec.gov and on the ISA's
website at http://www.magna.isa.gov.il, and will also be made available
without charge to all shareholders by contacting Noa Rosenberg-Segalovitz,
Adv. of Goldfarb, Levy, Eran, Meiri, Tzafrir & Co., Mr. Zisapel's Israeli
legal counsel, at the address or telephone number set forth below.
Shareholders are urged to read these materials carefully before making any
decision with respect to the tender offer.

About RADVISION: RADVISION is the industry's leading provider of
market-proven products and technologies for unified visual communications
over IP and 3G networks. With its complete set of standards-based video
networking infrastructure and developer toolkits for voice, video, data and
wireless communications, RADVISION is driving the unified communications
evolution by combining the power of video, voice, data and wireless - for
high definition videoconferencing systems, innovative converged mobile
services, and highly scalable video-enabled desktop platforms on IP, 3G and
emerging next-generation networks. For more information about RADVISION,
visit http://www.radvision.com.

About Zohar Zisapel: Mr. Zisapel served as the Chairman of the Board of
Directors of RADVISION from November 1992 until August 1999 and again assumed
that position in April 2001. During the last several years, Mr. Zisapel has
been engaged primarily in the management of high technology companies. Mr.
Zisapel is a founder and chairman of the board of directors of RAD Data
Communication Ltd. and he serves as a Chairman of other public companies,
including RADCOM Ltd., Ceragon Networks Ltd. and as a director of Amdocs Ltd.
Mr. Zisapel holds a B.Sc. and M.SC. degrees from the Technion - Israel
Institute of Technology and an MBA. degree from Tel Aviv University.

Forward-Looking Statements: This press release may contain
forward-looking statements that are subject to risks and uncertainties. The
accuracy of such statements is subject to a number of risks, uncertainties
and assumptions that may cause actual results to differ materially from those
projected, including, but not limited to, general business conditions in the
industry, changes in demand for products, the timing and amount or
cancellation of orders and other risks detailed from time to time in
RADVISION's filings with the Securities Exchange Commission, including its
Annual Report on Form 20-F. These documents contain and identify other
important factors that could cause actual results to differ materially from
those contained in these forward-looking statements. Shareholders and other
readers are cautioned not to place undue reliance on these forward-looking
statements, which speak only as of the date on which they are made. Mr.
Zisapel undertakes no obligation to update publicly or revise any
forward-looking statement.

CONTACT:
    Goldfarb, Levy, Eran, Meiri, Tzafrir & Co.
    2 Weizmann Street
    Tel Aviv 64239, Israel
    Telephone: +(972)-3-608-9999