One hundred four patients (71 males, 33 females) with acute gonococcal urethritis or cervicitis were treated with a single oral 250 mg dose of ciprofloxacin at Jos University Teaching Hospital, Jos, Nigeria. All gonococcal strains were isolated from appropriate pre-treatment swabs. Penicillinase-producing Neisseria gonorrhoeae (PPNG) accounted for 72.8% of all isolates. In vitro sensitivity of gonococcal isolates to ciprofloxacin was 100%, while that to penicillin, ampicillin and co-trimoxazole was below 15%. Of the 104 patients treated with ciprofloxacin, 73 (70%) attended a follow-up visit. Seventy-three (100%) patients showed clinical cure and elimination of N. gonorrhoeae from the respective site of infection. Post-gonococcal urethritis or cervicitis believed to be due to concomitant chlamydial infection was found in 22 (30.1%) patients--18 males and four females. No adverse reactions were reported by any patient. Our findings show that a single oral dose of ciprofloxacin (250 mg) is well tolerated and effective in the treatment of uncomplicated gonorrhoea and is particularly useful in regions with a high prevalence of PPNG.