This study determined the prevalence of Trichomonas vaginalis in young men who were at high risk for sexually transmitted diseases; compared different diagnostic tests for trichomonads; and compared sexual behavior of men with positive and negative trichomonas test results. Men (85) aged 16-22 years inclusive, were recruited from a job-training program to participate in this study. Urethral specimens were obtained after prostatic massage for the isolation of Neisseria gonorrhoeae, Chlamydia trachomatis, and trichomonads. The diagnosis of trichomonas infection was made by urethral culture, urine sediment culture, direct examination of urine sediment, direct specimen test (DFA), and Papanicolaou (PAP) smear of urethral swab. Trichomonas vaginalis was seen in 58% of the men, gonorrhoea in 23.5%, chlamydia in 29%, pediculosis in 6%, and condyloma acuminata in 7%, respectively. There was no statistically significant difference in age of the participants, frequency of intercourse, and number of sexual partners in the last 3 months in men with positive and negative trichomonas test results. After controlling for gonorrhoea, pyuria was significantly associated with trichomonas-positive urine (P = .01). No single test was ideal for the diagnosis of trichomonas infection. Using a combination of urethral culture and urine sediment culture as the "gold standard," DFA was 60% sensitive and 73.0% specific. However, urine sediment culture along with DFA identified 94% of all men with positive trichomonas test results.