X0201 4 2003-09-16 0 0000820237 GEN PROBE INC GPRO 0001230054 NORDHOFF HENRY L GEN-PROBE INCORPORATED 10210 GENETIC CENTER DRIVE SAN DIEGO CA 92121 1 1 0 0 CEO and President Common Stock 2003-09-16 4 M 0 26541 24.58 A 40627 D Common Stock 2003-09-16 4 M 0 20459 24.58 A 61086 D Common Stock 2003-09-16 4 S 0 47000 57.3623 D 4086 D Employee Stock Option (Right to Buy) 24.58 2003-09-16 4 M 0 26541 0 D 2011-09-01 Common Stock 26541 3948 D Employee Stock Option (Right to Buy) 24.58 2003-09-16 4 M 0 20459 0 D 2012-06-01 Common Stock 20459 260829 D The sales reported in this Form 4 were effected pursuant to a Rule 10b-5-1 trading plan adopted by the reporting person on September 15, 2003. Option vests as follows: 25% on 9/1/02; 1/48th vesting monthly thereafter following three years. Option vests as follows: 25% on 6/1/03; 1/48th vesting monthly thereafter following three years. /s/ R. William Bowen, Attorney-in-Fact 2003-09-18