Of 297 women attending a sexually transmitted disease clinic who were examined for the presence of mucopurulent cervicitis, 96 (32%) satisfied the diagnostic criteria. Mucopurulent cervicitis was strongly associated with the isolation of Chlamydia trachomatis and Neisseria gonorrhoeae. It was also associated with bacterial vaginosis, the use of oral contraceptives, and sexual contact with men who had non-gonococcal urethritis. Conversely, the presence of opaque cervical secretions did not show these associations, and the results indicated no difference in genital infections in women with clear cervical secretions whether or not more than 10 polymorphonuclear leucocytes per field (at a magnification of x 1000) were present. The findings support the suggestion that mucopurulent cervicitis is a definite clinical entity that requires investigation and treatment.