Human papillomavirus (HPV) infection, which has been linked to cervical dysplasia and carcinoma, causes one of the most frequently diagnosed sexually transmitted diseases (STDs) in the United States. To determine the prevalence of subclinical HPV infection, to detect any association with dysplasia, and to investigate risk factors, the author studied 249 sexually active adolescent girls and young women in a high-risk population by questionnaire, pelvic examination, cytology, and dot blot nucleic acid hybridization. The prevalence of subclinical HPV infection of the cervix was 10.4%. HPV-DNA positivity was associated with dysplasia, an increased number of sexual partners, and the part-time use of a birth control method. No association was found between subclinical HPV infection and race, cigarette smoking, oral contraceptive use, or the presence of other STDs. The use of HPV screening methods should be considered in select high-risk persons or groups.