To determine the effect of human immunodeficiency virus (HIV) infection on cervical histology, 32 known HIV-seropositive women underwent cervical colposcopic evaluation. All had cervical cytology, colposcopically directed biopsy, and T-cell studies performed. Thirteen of 32 patients (41%) had cervical intraepithelial neoplasia (CIN). Another 14 of 32 patients (44%) had histologic evidence of cervicitis. Abnormal cytology, noted in only three women, suggested CIN in one and inflammatory atypia in two. All (five of five) patients with a clinical diagnosis of AIDS had CIN, compared with 30% (eight of 27) of non-AIDS HIV-positive patients (P less than .05). Patients diagnosed with CIN had significantly lower CD4 cell counts (221/mm3 versus 408/mm3; P less than .06) and CD4:CD8 ratios (0.33 versus 0.62; P less than .02) than those without CIN. Patients with cervicitis had greater T-cell immunosuppression than did those with normal histology. In addition, patients with AIDS were more likely to have higher-grade lesions than were non-AIDS HIV-seropositive patients. Seven of 12 CIN specimens available for analysis by polymerase chain reaction using consensus sequence primers detected human papillomavirus (HPV) DNA, including three patients with three or more HPV types. Our data suggest that abnormal cervical pathology is common among HIV-positive women and that cytologic screening is not predictive of CIN in this population. In addition, the presence and severity of cervical dysplasia correlates with quantitative T-cell function. We strongly recommend that cervical colposcopy be part of the routine management of HIV-seropositive women.