Squamous cell carcinoma of the anus and HIV infection. We retrospectively reviewed six patients with squamous cell carcinoma of the anus (SCCA) and human immunodeficiency virus (HIV) infection treated between 1985 and 1988. All six patients were homosexual men. Five patients had AIDS and one was HIV-positive. The most common symptoms and signs were pain (n = 5), mass (n = 5), and bleeding (n = 5). The average tumor size was 3.2 cm with a range of 1-10 cm. Five tumors were located in the anal canal and one at the anodermal junction. One patient was treated with biopsy alone, one with local excision, one with wide local excision and radiation therapy, and two with diverting colostomy. The average follow-up was 8 months. Of the five AIDS patients, two died, one was transferred to a hospice facility, one was lost to follow-up, and one remains alive 1 year following treatment. The HIV-positive patient died secondary to metastatic SCCA. This group of patients raises the question of a possible association between HIV and SCCA. 