Gonococcal infections caused by antimicrobial-resistant strains of Neisseria gonorrhoeae have spread into many geographic areas and have increased in prevalence since the mid 1970s. Surveillance of antimicrobial-resistant gonococcal strains of Jamaica from 1981 to 1983 indicated that fewer than 3% of strains of produced beta-lactamase (penicillinase-producing Neisseria gonorrhoeae); approximately 4% of strains were resistant to penicillin, and 12% were resistant to tetracycline. To measure the frequency and nature of antimicrobial resistance in Neisseria gonorrhoeae isolates in Kingston, Jamaica, from 1990 to 1991 and to assess the effectiveness of prescribed treatment regimens. Urethral isolates of Neisseria gonorrhoeae from 116 heterosexual men with uncomplicated gonorrhea, representing 7.1% (116/1633) men attending the STD Comprehensive Health Centre from October 1990 through March 1991 who had positive Gram-stained smears, were characterized by auxotype, serovar, presence of the TetM determinant, and plasmid content. Antimicrobial susceptibilities to penicillin, cefoxitin, ceftriaxone, ciprofloxacin, tetracycline, and spectinomycin were determined by an agar dilution method. A total of 80.2% (93/116) of the isolates exhibited plasmid-mediated resistance to penicillin, tetracycline, or both: penicillinase-producing Neisseria gonorrhoeae (13/116; 11.2%), tetracycline-resistant Neisseria gonorrhoeae (25/116; 21.6%), and penicillinase-producing/tetracycline-resistant Neisseria gonorrhoeae, (55/116;47.4%). Isolates with chromosomally mediated resistance to penicillin, tetracycline, or both, accounted for 5.2% (6/116) of the isolates. Penicillinase-producing Neisseria gonorrhoeae, tetracycline-resistant Neisseria gonorrhoeae, and penicillinase-producing/tetracycline-resistant Neisseria gonorrhoeae belonging to multiple auxotype/serovar classes were isolated repeatedly through the study period. Infections caused by Neisseria gonorrhoeae exhibiting plasmid-mediated resistance to penicillin, tetracycline, or both, have become prevalent and endemic in Kingston, Jamaica. Therefore, all gonococcal infections should be treated with antimicrobial therapies known to be active against penicillin-resistant and tetracycline-resistant organisms to reduce gonorrhea transmission.