<ARTICLE> 5 <LEGEND> THIS SCHEDULE CONTAINS FINANCIAL INFORMATION EXTRACTED FROM THE UNAUDITED FINANCIAL STATEMENTS OF NETWORK-1 SECURITY SOLUTIONS, INC. FOR THE PERIOD ENDED JUNE 30, 1998 AND IS QUALIFIED IN ITS ENTIRETY BY REFERENCE TO SUCH FINANCIAL STATEMENTS. </LEGEND> <PERIOD-TYPE> 6-MOS <FISCAL-YEAR-END> DEC-31-1998 <PERIOD-START> JAN-01-1998 <PERIOD-END> JUN-30-1998 <CASH> 634,000 <SECURITIES> 0 <RECEIVABLES> 697,000 <ALLOWANCES> 88,000 <INVENTORY> 15,000 <CURRENT-ASSETS> 1,278,000 <PP&E> 769,000 <DEPRECIATION> 446,000 <TOTAL-ASSETS> 3,129,000 <CURRENT-LIABILITIES> 3,707,000 <BONDS> 0 <PREFERRED-MANDATORY> 0 <PREFERRED> 5,000 <COMMON> 17,000 <OTHER-SE> (600,000) <TOTAL-LIABILITY-AND-EQUITY> 3,129,000 <SALES> 412,000 <TOTAL-REVENUES> 902,000 <CGS> 395,000 <TOTAL-COSTS> 667,000 <OTHER-EXPENSES> 1,769,000 <LOSS-PROVISION> 18,000 <INTEREST-EXPENSE> 438,000 <INCOME-PRETAX> (1,990,000) <INCOME-TAX> 0 <INCOME-CONTINUING> (1,990,000) <DISCONTINUED> 0 <EXTRAORDINARY> 0 <CHANGES> 0 <NET-INCOME> (1,990,000) <EPS-PRIMARY> (1.17) <EPS-DILUTED> (1.17)