OBJECTIVE:To evaluate prospectively the safety of the infrared coagulator (IRC) as a treatment for anal high-grade squamous intraepithelial lesions (HSILs) in HIV-infected individuals and to seek preliminary evidence for efficacy. METHODS:HIV-infected patients with ≤3 biopsy-proven internal anal HSILs received office-based treatment with the IRC at participating AIDS Malignancy Consortium sites. Treatments were performed during high-resolution anoscopy (HRA) under local anesthesia. Patients were reevaluated at 3 months, and persistent lesions could be retreated. Patients were evaluated every 3 months for a year with anal cytology and HRA with biopsy. Human papillomavirus (HPV) DNA was measured at baseline and at follow-up using MY09/MY11 L1 polymerase chain reaction. RESULTS:A total of 44 HSILs were treated from 16 men and 2 women. HPV 16 was the most common HPV type identified. There was no consistent change in HPV type or viral load in patients before and after treatment with the IRC. No procedure-related severe adverse events were reported. Twelve patients reported mild or moderate anal/rectal pain or bleeding. CONCLUSIONS:The IRC is a well-tolerated method of treating discrete anal canal HSILs in HIV-infected patients. A larger study to characterize its efficacy better in the management of HSILs in HIV-infected individuals is warranted.