Twenty-one human immunodeficiency virus (HIV) seropositive patients were studied to determine the prevalence of cervical dysplasia, the distribution of human papilloma virus (HPV) subtypes, and the utility of cytologic diagnosis in this population. The patients ranged in age from 18 to 41 years. HIV infection was diagnosed in all patients by ELISA method and confirmed by Western blot. Patients were interviewed to document risk factors for HIV infection and cervical dysplasia. All were examined colposcopically and identifiable lesions were biopsied. In patients with normal colposcopic findings four quadrant biopsies were performed. Cervical and endocervical smears were obtained on all patients at the time of colposcopy and blood was collected for T-cell studies. Eighteen patients (86%) had abnormal cytologic findings. The Pap smear was able to identify 10 of 13 biopsy-proven epithelial abnormalities. In 14 patients there was sufficient tissue for HPV typing by in situ hybridization; the HPV subtypes identified were 6/11 (10 patients), 16/18 (9 patients), and 31/33/35 (9 patients). Dysplasia was present in 11/14 (79%) of the specimens submitted for subtyping. The absolute CD4 cell counts were 342 per mm3 for the dysplasia group and 281 per mm3 for the patients without dysplasia. Patients with dysplasia did not differ significantly from patients without dysplasia in regard to risk factors for cervical dysplasia, including history of STD, tobacco use, multiple sexual partners, age at first coitus, and parity. In addition, history of medication use and risk factors associated with HIV infection were similar in both groups.(ABSTRACT TRUNCATED AT 250 WORDS)