UNITED STATES
                       SECURITIES AND EXCHANGE COMMISSION
                             Washington, D.C. 20549

                                 SCHEDULE 13D/A
                                (Amendment No. 4)
                    Under the Securities Exchange Act of 1934

                                 RADVISION LTD.
                                 --------------
                                (Name of Issuer)

                 Ordinary Shares, par value NIS 0.10 per share
                 ---------------------------------------------
                         (Title of Class of Securities)

                                   M8186910 5
                                   ----------
                                 (CUSIP Number)

                               Steven J. Glusband
                          Carter Ledyard & Milburn LLP
                     2 Wall Street, New York, New York 10005
                                 (212) 732-3200
            --------------------------------------------------------
            (Name, Address and Telephone Number of Person Authorized
                     to Receive Notices and Communications)

                               December 15, 2008
             -------------------------------------------------------
             (Date of Event which Requires Filing of this Statement)

If the filing person has previously filed a statement on Schedule 13G to report
the acquisition that is the subject of this Schedule 13D, and is filing this
schedule because of Rule 13d-1(e), Rule 13d-1(f) or Rule 13d-1(g), check the
following box [ ]

Note: Schedules filed in paper format shall include a signed original and five
copies of the schedule, including all exhibits. See ss. 240.13d-7 for other
parties to whom copies are to be sent.

*The remainder of this cover page shall be filled out for a reporting person's
initial filing on this form with respect to the subject class of securities, and
for any subsequent amendment containing information which would alter
disclosures provided in a prior cover page.

The information required on the remainder of this cover page shall not be deemed
to be "filed" for the purpose of Section 18 of the Securities Exchange Act of
1934 ("Act") or otherwise subject to the liabilities of that section of the Act
but shall be subject to all other provisions of the Act (however, see the
Notes).








CUSIP No.  M8186910 5

1   NAME OF REPORTING PERSON: Zohar Zisapel

    I.R.S. IDENTIFICATION NO. OF ABOVE PERSON (ENTITIES ONLY): Not applicable.

2   CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP:                    (a) [ ]
                                                                         (b) [ ]

3   SEC USE ONLY

4   SOURCE OF FUNDS: PF

5   CHECK BOX IF DISCLOSURE OF LEGAL PROCEEDINGS IS REQUIRED PURSUANT TO
    ITEMS 2(d) or 2(e):                                                      [ ]

6   CITIZENSHIP OR PLACE OF ORGANIZATION:  Israel

NUMBER OF    7     SOLE VOTING POWER:  4,357,688 Ordinary Shares*
SHARES
BENEFICIALLY 8     SHARED VOTING POWER:  187,213 Ordinary Shares
OWNED BY
EACH         9     SOLE DISPOSITIVE POWER:  4,357,688 Ordinary Shares*
REPORTING
PERSON WITH  10    SHARED DISPOSITIVE POWER:  187,213 Ordinary Shares

11  AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON
    4,544,901 Ordinary Shares*

12  CHECK BOX IF THE AGGREGATE AMOUNT IN ROW (11) EXCLUDES CERTAIN SHARES    [ ]

13  PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW (11):  23.15%**

14  TYPE OF REPORTING PERSON:  IN

-----------------

*    Includes  97,500  Ordinary  Shares  issuable  upon the  exercise of options
     granted to the  Reporting  Person  exercisable  as of December 16, 2008 and
     within 60 days thereafter.

**   Based on 19,631,713 Ordinary Shares that the Issuer advised were issued and
     outstanding  (which  excludes  2,884,510  Ordinary  Shares held as treasury
     stock) as of December 16, 2008.


                                       2




Item 1. Security and Issuer
        -------------------

         This Amendment No. 4 to the Statement on Schedule 13D dated relates to
the Ordinary Shares, par value NIS 0.10 per share (the "Ordinary Shares"), of
RADVISION Ltd. (the "Issuer"), an Israeli company whose principal executive
offices are located at 24 Raoul Wallenberg Street, Tel Aviv 69719, Israel.

Item 2. Identity and Background
        -----------------------

         ITEM 2 OF THIS STATEMENT IS HEREBY AMENDED AND RESTATED TO READ IN ITS
ENTIRETY AS FOLLOWS:

         Mr. Zohar Zisapel, a citizen of Israel, serves as chairman of the board
of directors of the Issuer. Mr. Zisapel is a founder and director of several
other companies which, together with the Issuer and its other subsidiaries and
affiliates, are known as the RAD-BYNET group. Mr. Zisapel's business address is
24 Raoul Wallenberg Street, Tel Aviv 69719, Israel.

         During the last five years, Mr. Zisapel has not been convicted in any
criminal proceeding (excluding traffic violations or similar misdemeanors), nor
has he been a party to a civil proceeding of a judicial or administrative body
of competent jurisdiction as a result of which proceeding he was or is subject
to a judgment, decree or final order either enjoining future violations of, or
prohibiting or mandating activities subject to, United States federal or state
securities laws, or finding any violation with respect to such laws.

Item 3. Source and Amount of Funds or Other Consideration
        -------------------------------------------------

         ITEM 3 OF THIS STATEMENT IS HEREBY AMENDED TO ADD THE FOLLOWING:

         From the last report filed on November 24, 2008 through December 16,
2008, Mr. Zisapel purchased an aggregate of 169,774 Ordinary Shares of the
Issuer in a series of transactions, all of which were purchased by Lomsha Ltd.,
an Israeli company controlled by him. The aggregate purchase price for such
169,774 Ordinary Shares was approximately $1,018,644, all of which amount was
paid by the Reporting Person from his personal funds.

Item 4. Purpose of Transaction
        ----------------------

         ITEM 4 OF THIS STATEMENT IS HEREBY AMENDED TO ADD THE FOLLOWING:

         The 169,774 Ordinary Shares purchased by Mr. Zisapel during the period
from November 24, 2008 through December 16, 2008 were purchased for investment
purposes. Mr. Zisapel currently does not have any plan or proposal, which
relates to or would result in:

          (a) the  acquisition  by any person of  additional  securities  of the
     Issuer, or the disposition of securities of the Issuer;

          (b)  an  extraordinary  corporate  transaction,   such  as  a  merger,
     reorganization,  or  liquidation,  involving  the  Issuer  or  any  of  its
     subsidiaries;

          (c) a sale or  transfer  of a  material  amount  of the  assets of the
     Issuer or any of its subsidiaries;


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          (d) any change in the present  board of directors or management of the
     Issuer,  including  any plan or  proposal  to change  the number or term of
     directors or to fill any existing vacancies on the board;

          (e) any  material  change in the  present  capitalization  or dividend
     policy of the Issuer;

          (f) any other  material  change in the Issuer's  business or corporate
     structure;

          (g) changes in the Issuer's  charter or by-laws or other actions which
     may impede the acquisition of control of the Issuer by any person;

          (h) a class of securities of the Issuer being delisted from a national
     securities  exchange  or  ceasing  to  be  authorized  to be  quoted  in an
     inter-dealer   quotation  system  of  a  registered   national   securities
     association;

          (i) a class of equity  securities of the Issuer becoming  eligible for
     termination of registration  pursuant to Section 12(g)(4) of the Securities
     Exchange Act of 1934; or

          (j) any action similar to any of those enumerated above.

         Mr. Zohar Zisapel intends to review his investment in the Issuer and
         may, based on such review as well as other factors (including, among
         other  things, his evaluation of the Issuer's business, prospects and
         financial condition, amounts and prices of available securities of the
         Issuer, the market for the Issuer securities, other opportunities
         available to Mr. Zohar Zisapel and general market and economic
         conditions), acquire additional securities of the Issuer, on the open
         market or in privately negotiated transactions. Mr. Zohar Zisapel
         reserves the right at any time to change his present intention with
         respect to any or all of the matters referred to in this Item 4, or to
         dispose of any or all of the securities of the Issuer purchased by him.

Item 5. Interest in Securities of the Issuer
        ------------------------------------

         ITEM 5 OF THIS STATEMENT IS HEREBY AMENDED AND RESTATED TO READ IN ITS
ENTIRETY AS FOLLOWS:

         (a) Mr. Zisapel is the beneficial owner of 4,544,901 Ordinary Shares of
the Issuer, which constitute approximately 23.15% of the 19,631,713 Ordinary
Shares of the Issuer that the Issuer advised were issued and outstanding (which
excludes 2,884,510 Ordinary Shares held as treasury stock) as of December 16,
2008. Of such shares, (i) 3,013,044 Ordinary Shares were held of record by the
Reporting Person; (ii) 97,500 Ordinary Shares were issuable upon the exercise of
options granted to the Reporting Person exercisable as of December 16, 2008 or
within 60 days thereafter; (iii) 936,288 Ordinary Shares were held of record by
Lomsha Ltd., an Israeli company controlled by the Reporting Person; (iv) 310,856
Ordinary Shares were held of record by Michael and Klil Holdings (93) Ltd., an
Israeli company controlled by the Reporting Person; and (v) 187,213 Ordinary
Shares were held of record by RAD Data Communications Ltd., an Israeli company.
The Reporting Person is a principal shareholder and Chairman of the Board of
Directors of RAD Data Communications Ltd. The Reporting Person and his brother
Mr. Yehuda Zisapel have shared voting and dispositive power with respect to the
shares held by RAD Data Communications Ltd.

         (b) Mr. Zohar Zisapel has sole power to vote or direct the vote and the
sole power to dispose or direct the disposition of 3,013,044 Ordinary Shares of
the Issuer held by him directly.

                  Mr. Zohar Zisapel has sole power to vote or direct the vote
and the sole power to dispose or direct the disposition of 97,500 Ordinary
Shares of the Issuer underlying the options held by him directly that are
exercisable as of December 16, 2008 or within 60 days thereafter.



                                        4




                  Mr. Zohar Zisapel has sole power to vote or direct the vote
and the sole power to dispose or direct the disposition of 936,288 Ordinary
Shares of the Issuer held of record by Lomsha Ltd.

                  Mr. Zohar Zisapel has sole power to vote or direct the vote
and the sole power to dispose or direct the disposition of 310,856 Ordinary
Shares of the Issuer held of record by Michael and Klil Holdings (93) Ltd.

                  Mr. Zohar Zisapel and his brother Mr. Yehuda Zisapel have
shared power to vote or direct the vote and the shared power to dispose or
direct the disposition of the 187,213 Ordinary Shares of the Issuer held of
record by RAD Data Communications Ltd.

         (c) The following table sets forth all the transactions in the Ordinary
Shares of the Issuer effected by Mr. Zohar Zisapel since November 24, 2008. All
such purchases were made by Lomsha Ltd., an Israeli company controlled by Zohar
Zisapel. All such transactions were open market purchases effected on the NASDAQ
Global Market.


                                  Number of Ordinary
         Date of Purchase          Shares Purchased          Price Per Share ($)
         ----------------         ------------------         -------------------
            12/04/2008                  25,080                       6.00
            12/05/2008                  16,003                       6.00
            12/12/2008                   1,965                       6.00
            12/15/2008                  126,726                      6.00

         Except for such transactions, Mr. Zohar Zisapel has not effected any
transactions in the Ordinary Shares of the Issuer since November 24, 2008.

         (d) No person other than Mr. Zohar Zisapel has the right to receive or
the power to direct the receipt of dividends from, or the proceeds from the sale
of, the shares reported above in this Item 5(c).

         (e) Not applicable.

Item 6. Contracts, Arrangements, Understandings or Relationships with Respect to
        Securities of the Issuer
        ------------------------

         None.

Item 7. Material to be Filed as Exhibits.
        ---------------------------------

         None.



                                        5






                                    SIGNATURE


         After reasonable inquiry and to the best of our knowledge and belief,
we certify that the information set forth in this statement is true, complete
and correct.



         Date: December 17, 2008



                                            /s/Zohar Zisapel
                                            ----------------
                                            Zohar Zisapel





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