SECURITIES AND EXCHANGE COMMISSION
                              Washington, DC 20549

                                   FORM 12b-25

                                                  Commission File Number 1-14896


                           NOTIFICATION OF LATE FILING

(Check One):
|X| Form 10-KSB   |_| Form 11-K   |_| Form 20-F   |_| Form 10-Q   |_| Form N-SAR

               For Period Ended: December 31, 1998
                                ------------------------------

               [ ] Transition Report on Form 10-K
               [ ] Transition Report on Form 20-F
               [ ] Transition Report on Form 11-K
               [ ] Transition Report on Form 10-Q
               [ ] Transition Report on Form N-SAR

               For the Transition Period Ended:             
                                               ---------------------------------

     Nothing in this form shall be construed to imply that the Commission has
verified any information contained herein.

     If the notification relates to a portion of the filing checked above,
identify the Item(s) to which the notification relates:
                                                       -------------------------

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                                     PART I
                             REGISTRANT INFORMATION

                       Network-1 Security Solutions, Inc.
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                            Full Name of Registrant


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                           Former Name if Applicable

                              
                       1601 Trapelo Road, Reservoir Place
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           Address of Principal Executive Office (Street and Number)

                          Waltham, Massachusetts 02451
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                            City, State and Zip Code

                                    PART II
                            RULES 12b-25(b) AND (c)

     If the subject report could not be filed without unreasonable effort or
expense and the registrant seeks relief pursuant to Rule 12b-25(b), the
following should be completed. (Check appropriate box.)  |_| Yes  |_| No


|X| | (a) The reasons described in reasonable detail in Part III of this form
    |     could not be eliminated without unreasonable effort or expense;
    |
|X| | (b) The subject annual report, semi-annual report, transition report on
    |     Form 10-K, 20-F, 11-K or N-SAR, or portion thereof, will be filed on
    |     or before the 15th calendar day following the prescribed due date; or
    |     the subject quarterly report or transition report on Form 10-Q, or
    |     portion thereof will be filed on or before the fifth calendar day
    |     following the prescribed due date; and
    |  
|_| | (c) The accountant's statement or other exhibit required by Rule 12b-25(c)
    |     has been attached if applicable.


                                    PART III
                                   NARRATIVE

State below in reasonable detail the reasons why Form 10-K, 11-K, 20-F, 10-Q,
N-SAR, or the transition report or portion thereof, could not be filed within
the prescribed time period. 

      The Company is unable to file its Form 10-KSB for the year ended December
31, 1998 at this time because there is a material outstanding issue with respect
to the extent to which revenue can be recognized from a particular ongoing
consulting project. The Company believes that this issue will be resolved within
the next ten days based upon additional which can not be reasonably obtained as
of the date hereof.


                                    PART IV
                               OTHER INFORMATION

(1)  Name and telephone number of person to contact in regard to this
     notification   

Murray P. Fish                                      (781)        522-3400
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       (Name)                                    (Area Code) (Telephone Number)

(2)  Have all other periodic reports required under Section 13 or 15(d) of the
     Securities Exchange Act of 1934 or Section 30 of the Investment Company Act
     of 1940 during the preceding 12 months or for such shorter period that the
     registrant was required to file such report(s) been filed? If answer is no,
     identify report(s). |X| Yes |_| No



(3)  Is it anticipated that any significant change in results of operation for 
     the corresponding period for the last fiscal year will be reflected by the
     earnings statements to be included in the subject report or portion
     thereof? |X| Yes |_| No
    
     If so: attach an explanation of the anticipated change, both narratively
     and quantitatively, and, if appropriate, state the reasons why a reasonable
     estimate of the results cannot be made.


                       Network-1 Security Solutions, Inc.
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                  (Name of Registrant as Specified in Charter)

            Has caused this notification to be signed on its behalf
                  by the undersigned hereunto duly authorized.


Date March 31, 1999               By 
    -----------------------       -------------------------------------------
                                     Murray P. Fish, Chief Financial Officer



Instruction: The form may be signed by an executive officer of the registrant or
by any other duly authorized representative. The name and title of the person
signing the form shall be typed or printed beneath the signature. If the
statement is signed on behalf of the registrant by an authorized representative
(other than an executive officer), evidence of the representative's authority to
sign on behalf of the registrant shall be filed with the form.

                                    ATTENTION
     Intentional misstatements or omissions of fact constitute Federal criminal
violations. (See 18 U.S.C. 1001)


                                  Attachement

                 Form 12b-25/Network-1 Security Solutions, Inc.

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(3)   The Company anticipates that it will incur a net loss of approximately
      $5,700,000 for the year ended December 31, 1998 as compared to a net loss
      of $2,390,000 for the year ended December 31, 1997.