Three hundred twenty-five men with confirmed urethral trichomoniasis were seen at sexually transmitted diseases clinics in Harare, Zimbabwe, in 1983-1984. The mean age of these patients was 30.4 years. The most common symptoms were urethral discharge and urethral irritation. Symptoms in 252 patients (78%) had been present for more than four weeks. Only 1.5% of 5548 patients with nontrichomonal nongonococcal urethritis had had symptoms for this length of time. In most patients with trichomoniasis (99.4%), the discharge was milky white and fluid in nature; when a smear of the discharge was made on a glass slide, small clumps of material were noted. Microscopic examination of the gram-stained smear showed relatively few polymorphonuclear leukocytes but many epithelial cells. Although Trichomonas vaginalis was readily demonstrated by microscopy of both urethral secretions and centrifuged deposits of urine, the organism was cultured only from urethral exudates. Concomitant infection with T. vaginalis was uncommon in patients with proved gonococcal urethritis. Treatment of trichomoniasis in men with a single 2-g dose of metronidazole was unsuccessful in 42.9% of cases. However, treatment with 400 mg of metronidazole thrice daily for five days gave a cure rate of 100%.