Since the recognition of penicillinase-producing strains of N gonorrhoeae (PPNG) in 1976, these organisms have attained a worldwide distribution. The treatment of choice for infection due to PPNG has generally been spectinomycin administered im. In 1981, however, an infection from California was reported to be due to a strain of PPNG that was also resistant to spectinomycin (MIC, greater than 2,048 micrograms/ml) [1]. Throughout 1982, seven such isolates were reported worldwide [2], and in January 1983 an epidemiologically linked series of 27 cases of infection due to spectinomycin-resistant PPNG occurred in Korea. Because of the apparent declining utility of spectinomycin, we studied the efficacy and safety of aztreonam, a synthetic monobactam antibiotic from the Squibb Institute for Medical Research (Princeton, NJ) [3], in the treatment of acute uncomplicated gonococcal urethritis in men. Men with gonococcal urethritis were randomly treated with either 1 g of aztreonam or 2 g of spectinomycin im. Of the 112 men so treated, 93 could ultimately be evaluated: 51 who received aztreonam and 42 who received spectinomycin. Both drugs were 100% effective in the treatment of urethritis produced by both penicillin-sensitive and penicillin-resistant strains of gonococci. Furthermore, there were no reported side effects in either group and no laboratory abnormalities attributable to the aztreonam, with the exception of one patient with a minimally elevated level of serum glutamic oxaloacetic transaminase (serum glutamic pyruvic transaminase and alkaline phosphatase levels were normal).(ABSTRACT TRUNCATED AT 250 WORDS)