CUSIP No. 636518 10                                          Page 1 of 5 Pages

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

                                  SCHEDULE 13G


                    Under the Securities Exchange Act of 1934

                              (Amendment No. Three)*


                        NATIONAL INSTRUMENTS CORPORATION
- ------------------------------------------------------------------------------

                                (Name of Issuer)


                                  COMMON STOCK
- ------------------------------------------------------------------------------

                         (Title of Class of Securities)


                                    636518 10
- ------------------------------------------------------------------------------

                                 (CUSIP Number)


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

The information required in 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).







SEC 1745 (2-95)

                                Page 1 of 5 Pages






CUSIP No. 636518 10                                          Page 2 of 5 Pages



CUSIP No. 636518 10                       13G                 Page 2 of 5 Pages


   1    NAME OF REPORTING PERSON                                             
        S.S. OR I.R.S. IDENTIFICATION NO. OF ABOVE PERSON

        JEFFREY L. KODOSKY
   2    CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP*
        (a)   |_|
        (b)   |_|
   3    SEC USE ONLY


   4    CITIZENSHIP OR PLACE OF ORGANIZATION
        U.S.A.
                      5    SOLE VOTING POWER

     NUMBER OF             2,490,705
      SHARES
   BENEFICIALLY
     OWNED BY
       EACH
     REPORTING
    PERSON WITH
   6    SHARED VOTING POWER
        -0-

   7    SOLE DISPOSITIVE POWER
        2,490,705

   8    SHARED DISPOSITIVE POWER
        -0-

   9    AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON

        2,490,705

  10    CHECK BOX IF THE AGGREGATE AMOUNT IN ROW (9) EXCLUDES CERTAIN SHARES*

  11    PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW 9
        7.63%

  12    TYPE OF REPORTING PERSON*
        IN

                       *SEE INSTRUCTION BEFORE FILLING OUT







CUSIP No. 636518 10                                          Page 3 of 5 Pages


Item 1.
      (a)   Name of Issuer    National Intruments Corporation

      (b)   Address of Issuer's Principal Executive Offices
                              6504 Bridge Point Parkway
                              Austin, TX 78730-5039

Item 2.
      (a)   Name of Person Filing   Jeffrey L. Kodosky

      (b)   Address of Principal Business Office or, if none, Residence
                                    6504 Bridge Point Parkway
                                    Austin, TX 78730-5039

      (c)   Citizenship             
                                    U.S.A.

      (d)   Title of Class of Securities
                                    Common Stock

      (e)   CUSIP Number            
                                    N/A

Item 3. If this statement is filed pursuant to Rule 13d-1(b), or 13d-2(b),
        check whether the person is a:
    (a) |_| Broker or Dealer registered under Section 15 of the Act
    (b) |_| Bank as defined in section 3(a)(6) of the Act
    (c) |_| Insurance Company as defined in section 3(a)(19) of the Act
    (d) |_| Investment Company registered under section 8 of the Investment
            Company Act
    (e) |_| Investment Adviser registered under section 203 of the Investment
            Advisers Act of 1940
    (f) |_| Employee Benefit Plan, Pension Fund which is subject to the
            provisions of the Employee Retirement Income Security Act of 1974 or
            Endowment Fund, see ss.240.13d-1(b)(1)(ii)(F)
    (g) |_| Parent Holding Company, in accordance with ss.240.13d-1(b)(ii)(G)
            (Note: See Item 7)
    (h) |_| Group, in accordance with ss.240.13d-1(b)(1)(ii)(H)








CUSIP No. 636518 10                                          Page 4 of 5 Pages


Item 4.  Ownership

      (a)   Amount Beneficially Owned                                2,490,705*

      (b)   Percent of Class                                              7.63%

      (c)   Number of shares as to which such person has:

           (i) sole power to vote or to direct the vote              2,490,705*
          (ii) shared power to vote or to direct the vote                    0
         (iii) sole power to dispose or direct the disposition of    2,490,705*
          (iv) shared power to dispose or direct the disposition of          0



Item 5.  Ownership of Five Percent or Less of a Class

     If this  statement  is being  filed to report  the fact that as of the date
hereof the reporting  person has ceased to be the beneficial  owner of more that
five percent of the class of securities, check the following |_|.
         NOT APPLICABLE

Item 6.  Ownership of More than Five Percent on Behalf of Another Person.
         NOT APPLICABLE

Item 7.  Identification and Classification of the Subsidiary Which Acquired the
         Security Being Reported on By the Parent Holding Company.
         NOT APPLICABLE

Item 8.  Identification and Classification of Members of the Group
         NOT APPLICABLE

Item 9.  Notice of Dissolution of Group
         NOT APPLICABLE





* Includes 758,250 shares held in trusts and 232,500 shares held by a foundation
over which reporting person exerts voting and dispositive  control, but excludes
1,499,455 shares held by reporting person's spouse.






CUSIP No. 636518 10                                          Page 5 of 5 Pages

Item 10.
            By signing  below I certify  that,  to the best of my knowledge  and
belief, the securities referred to above were acquired in the ordinary course of
business  and were not acquired for the purpose of and do not have the effect of
changing or  influencing  the control of the issuer of such  securities and were
not acquired in connection  with or as a participant in any  transaction  having
such purposes or effect.


                                    SIGNATURE


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




                                          Date    February 17, 1998



                                          /s/ JEFFREY L. KODOSKY
                                          -------------------------------------
                                          Jeffrey L. Kodosky, VP Research and
                                          Development