Two hundred and sixty two male patients attending the Special Treatment Clinic (STC) of the University College Hospital, Ibadan between July and December 1989, were examined for Trichomonas vaginalis as a cause of non-gonococcal urethritis using both microscopic and culture methods. Thirteen of the 262 male patients were the sexual partners of trichomonas vaginalis infected women. While 47(17.9) percent of the 262 men investigated had gonococcal urethritis, 215(82.1 percent) had non-gonococcal urethritis out of whom 18(8.4 percent) had trichomonal urethritis. The age range of peak incidence among the patients investigated is 20-29 years. A significant difference (P < 0.001) between the number of male sexual contacts that were positive for trichomoniasis (38 percent) and other male patients included in this study (8.4 percent) was demonstrated. Culture of the samples from the male patients investigated gave the highest proportion (100 percent) of positive results. This indicates the superiority of culture methods over other methods of diagnosing trichomoniasis such as microscopic method routinely used in our centre.