Men and women with uncomplicated gonorrhea were randomly assigned to receive aqueous procaine penicillin G (2,400,000 U for men; 2,400,000 U daily for 2 days for women) or spectinomycin hydrochloride (2.0 g for men; 4.0 g for women). Among men who returned for post-treatment evaluation within 10 days, treatment failures were noted among 16 (20.3%) of 79 men who received penicillin and 8 (9.5%) of 84 men who received spectinomycin (P < 0.1). Similarly, 6 (13.3%) of 45 women who received penicillin and 3 (6.5%) of 46 women who received spectinomycin had positive endocervical cultures for Neisseria gonorrhoeae at the time of the post-treatment examination (P = not significant).