We tested 91 asymptomatic adolescent male detainees in a short-stay detention facility in Seattle, Washington for the presence of leukocyte esterase in first-catch urine and for Chlamydia trachomatis and Neisseria gonorrhoeae infection. C. trachomatis was isolated from 10 subjects (11 per cent) and N. gonorrhoeae from five (5 per cent). Dipsticks detected leukocyte esterase in the urine of all 15 subjects with either infection and of 13 subjects with neither infection. Detection of leukocyte esterase was 100 per cent sensitive, 83 per cent specific, and 54 per cent predictive for the presence of either organism.