Antibiotic resistance in Neisseria gonorrhoeae occurs worldwide and may limit the efficacy of treatment. This study reports the epidemiology and treatment outcome for 125 episodes of infection with antibiotic resistant gonococci diagnosed in Scotland in 1996. Infections with penicillinase producing N. gonorrhoeae (PPNG) and/or high level plasmid mediated tetracycline resistant N. gonorrhoeae (TRNG) and isolates showing reduced susceptibility to ciprofloxacin were more likely to belong to an unusual serovar and have been acquired abroad by heterosexual intercourse than isolates showing chromosomal resistance to penicillin or tetracycline, which were more likely to belong to a common serovar and to have been acquired in the United Kingdom by homosexual intercourse. Among the 88 episodes of infection whose outcome was known initial treatment with an antibiotic to which the isolate was resistant failed in nine out of 16 infections and in three out of the 72 infections treated with an antibiotic to which the organism was sensitive. In the case of high level plasmid mediated resistance, treatment with an inappropriate antibiotic always resulted in failure. Continuous monitoring of treatment outcome is essential to guide clinicians in prescribing the most appropriate antibiotic for individual patients.