Our clinical experience with loop electrosurgical excision as therapy for cervical intraepithelial neoplasia (CIN) in women infected with human immunodeficiency virus is described. Information for this analysis was obtained from a retrospective chart review of all women with biopsy-confirmed CIN treated by loop electrosurgical excision who attended our colposcopy clinic during January 1991 to September 1992. Outcomes in women known to be HIV-seropositive were compared to those in women of unknown HIV serostatus. Patients included in the analysis were followed for at least 6 months or until the documentation of recurrent/persistent CIN, and all had at least one post-treatment colposcopic examination, including endocervical curettage and cervical biopsy of any acetowhite lesions. Recurrent/persistent CIN following loop excision was documented in 56% (19 of 34) HIV-infected women compared with 13% (10 of 80) women of unknown serostatus (OR 8.9, P < 0.001). HIV-infected women had a significantly higher rate of recurrent/persistent CIN than women of unknown serostatus, regardless of grade of CIN. In HIV-infected women, recurrent/persistent CIN following loop excision developed in 20% (1 of 5) with CD4+ T-lymphocyte counts > 500 cells/microliters compared to 61% (11 of 18) with CD4+ counts < or = 500 cells/microliters (P = 0.13). Loop electrosurgical excision has a high failure rate in HIV-infected women, and this failure rate may increase as the level of immunosuppression increases.