5

THIS SCHEDULE CONTAINS SUMMARY FINANCIAL INFORMATION EXTRACTED FROM THE UNAUDITED FINANCIAL STATEMENTS OF NETWORK-1 SECURITY SOLUTIONS, INC. FOR THE PERIOD ENDED SEPTEMBER 30, 1998 AND IS QUALIFIED IN ITS ENTIRETY BY REFERENCE TO SUCH FINANCIAL STATEMENTS.

9-MOS DEC-31-1998 JAN-01-1998 SEP-30-1998 181,000 0 767,000 100,000 15,000 884,000 813,000 488,000 2,823,000 4,438,000 0 0 5,000 23,000 (1,643,000) 2,823,000 514,000 1,573,000 563,000 1,065,000 2,921,000 12,000 722,000 (3,147,000) 0 (3,147,000) 0 0 0 (3,147,000) (1.69) (1.69)