Specimens from the lower genital tract of 102 sexually active urban adolescent females were tested for the common sexually transmitted diseases (STDs). The results were correlated with concomitant clinical, demographic, and historic data. Forty-one percent (42/102) were infected with one or more of the following organisms: Chlamydia trachomatis (26/102), Trichomonas vaginalis (13/102), Neisseria gonorrhoeae (10/102), yeast (6/102), condyloma (5/102), and herpes simplex virus (1/44). Mixed infections were found in 13%. Fifty-nine percent were negative for any infectious agents. The presence of genitourinary symptoms were of no value in predicting an STD. The rate of positive physical findings was significantly higher in the STD-positive group than in the negative group (p = 0.03), but 28% of the STD-negative group had positive physical findings, and 50% of the STD-positive group had normal physical findings. A history of genitourinary complaints or presence of physical findings was not predictive of a positive STD culture. Oral contraceptive use of more than six months appears to be a risk factor for an STD. No other factors, including the number of sexual partners, were significantly correlated with the presence of an STD. This study supports the need for routine screening of sexually active urban adolescent girls for an STD.