TEL AVIV, Israel, April 30 /PRNewswire/ --     Zohar Zisapel announced today that he is commencing today a tender offer
to purchase 5.0% of the outstanding ordinary shares of RADVISION Ltd.
(Nasdaq: RVSN) (currently, 971,394 RADVISION shares) for $6.30 per share, net
to the seller in cash, less any required withholding taxes and without
interest. In the event that more than the maximum number of shares offered to
be purchased in the tender offer are tendered, Mr. Zisapel will purchase
shares on a pro rata basis.

The bidder, Mr. Zisapel, currently beneficially owns 4,767,401 RADVISION
shares, or approximately 24.5% of the outstanding shares, including 187,213
RADVISION shares as to which he has shared voting and dispositive power. In
addition, Mr. Zisapel holds options to acquire 101,250 RADVISION shares
exercisable within 60 days from the date of this announcement. If the full
number of shares is purchased in the tender offer, Mr. Zisapel will
beneficially own 5,738,795 RADVISION shares, or approximately 29.5% of the
outstanding shares, not including options.

On April 29, 2009, the last trading day on Nasdaq before commencement of
the offer, the closing sale price of the RADVISION shares was $7.06. On April
27, 2009, the last trading day on the Tel Aviv Stock Exchange before
commencement of the offer, the closing sale price of the RADVISION shares was
NIS 29.20 ($6.90 based on an exchange rate of NIS 4.233 per United States
dollar as of April 27, 2009).

The initial period of the tender offer and withdrawal rights are
scheduled to expire at 10:00 a.m., New York time, or 5:00 p.m., Israel time,
on Monday, June 1, 2009, unless the initial period is extended by Mr.
Zisapel. As required by Israeli law, if the conditions to the offer have been
satisfied (or waived, to the extent permitted by applicable law) as of the
completion of the initial offer period, Mr. Zisapel will provide an
additional period of four calendar days during which shareholders may tender
their shares. However, shareholders will have no withdrawal rights during
such additional four calendar day period.

The tender offer is conditioned upon: (1) RADVISION shares representing
5.0% of the outstanding shares and voting power of RADVISION (currently,
971,394 RADVISION shares) having been validly tendered and not withdrawn
prior to the completion of the initial offer period, (2) as required by
Israeli law, at the completion of the initial offer period, the aggregate
number of shares tendered in the offer (excluding shares tendered by
affiliates of Mr. Zisapel) being greater than the number of shares
represented by notices of objection to the offer, and (3) the fulfillment of
certain other conditions specified in the Offer to Purchase relating to the
tender offer. The tender offer is not conditioned on the receipt of financing
or the approval of the board of directors of RADVISION.

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 included as an
exhibit to the Tender Offer Statement on Schedule TO filed today 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 will only be made through the Offer to Purchase, Letter of
Transmittal and related tender offer documents. All holders of RADVISION
shares should read the tender offer materials, which are being filed today by
Mr. Zisapel, and the Tender Offer Solicitation/Recommendation Statement with
respect to the tender offer, which will be filed in due course 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 will be 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 our projections or forward-looking statements.
Stockholders 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. We undertake 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