The importance of Chlamydia trachomatis as a cause of genital tract infection in Caribbean countries is largely unknown. Two hundred and sixteen cervical and urethral specimens were collected from patients with cervicitis and urethritis attending a Sexually Transmitted Diseases (STD) Clinic, a Gynaecology Clinic and a Family Planning Clinic in Kingston. Specimens were tested for chlamydiae by direct immunofluorescence and cell culture methods. They were also investigated for N. gonorrhoeae infections. Seventy-two of 138 patients (52.2%) at the STD Clinic were positive for chlamydiae; 28 of 50 (56.0%) from the Gynaecology Clinic and 11 of 28 (39.3%) from the Family Planning Clinic were positive. The prevalence of C. trachomatis (52.3%) was higher than that of N. gonorrhoeae (11.1%) in all groups. The results indicate that C. trachomatis is a common cause of genital tract infections in Jamaica.