5

THIS SCHEDULE CONTAINS SUMMARY FINANCIAL INFORMATION EXTRACTED FROM AUDITED FINANCIAL STATEMENTS OF NETWORK-1 SECURITY SOLUTIONS, INC. FOR THE YEAR ENDED DECEMBER 31, 1997, AND FROM UNAUDITED FINANCIAL STATEMENTS FOR THE PERIOD ENDED MARCH 31, 1998 AND IS QUALIFIED IN ITS ENTIRETY BY REFERENCE TO SUCH FINANCIAL STATEMENTS.

YEAR 3-MOS DEC-31-1997 DEC-31-1998 JAN-01-1997 JAN-01-1998 DEC-31-1997 MAR-31-1998 60,000 67,000 0 0 505,000 346,000 70,000 60,000 15,000 15,000 525,000 383,000 766,000 768,000 366,000 404,000 2,404,000 2,094,000 1,186,000 2,666,000 0 0 0 0 5,000 5,000 17,000 17,000 (97,000) (594,000) 2,404,000 2,094,000 1,632,000 195,000 2,369,000 339,000 497,000 177,000 790,000 252,000 3,351,000 570,000 65,000 (10,000) 553,000 224,000 (2,390,000) (697,000) 0 0 (2,390,000) (697,000) 0 0 0 0 0 0 (2,390,000) (697,000) (1.29) (0.41) (1.29) (0.41)