A review of more than 1,000 medical records of the University of South Florida students screened for gonorrhea, Chlamydia trachomatis, and syphilis during a period of 1 year in 1986-1987 showed genital chlamydial infection to be the most prevalent of these sexually transmitted diseases (STDs). Among normal asymptomatic female students with no known recent STD contact, 6.9% had a positive chlamydial enzyme immunoassay. Female students with vaginal symptoms had a greater tendency to be positive, and 47.8% of those with a recent STD contact tested positive for chlamydia. Males with a clinical diagnosis of nonspecific urethritis had a 50% probability of having a positive chlamydia test. Data from this study clearly support a need for a screening policy and educational program on the campus to improve control of chlamydial infection.