The prevalence of sexually transmitted disease (STD) in adolescent girls aged 15-19 attending a department of genitourinary medicine was compared for the years 1972 and 1982. Data were obtained from the confidential register using the coding of the clinic returns to the Department of Health (form SBH 60). There were 1373 patients in 1972 and 1799 in 1982, 6.4% and 7% respectively of the total female clinic population. The prevalence of syphilis, gonorrhoea, and infection with Trichomonas vaginalis, herpes simplex virus, and warts was almost unchanged. Other conditions, which are not classified as STD, were largely responsible for the increase in new attendances, the prevalence of these conditions having nearly doubled over the ten year period. Thus an epidemic of STD has not been shown in this adolescent female population over the past decade.