Abstract This study of 106 cases of malignant tumors of the anus has shown that the diagnosis was often made late. In 15 percent of the patients the tumor was at the anal margin; in 61 percent, in the anal canal, and in 24 percent, the tumor was so extensive that its origin could not be determined clinically. In nearly half of the cases, the cancers were advanced and showed perirectal metastases. Surgical treatment was the ride, with local excision for carcinomas of the anal margin and abdominoperineal resection for tumors of the canal. The general prognosis over a period of several decades remains poor. We found a 20 percent 5 year survival rate for epidermoid carcinoma of the anal canal, excluding deaths from causes other than cancer during the follow-up period.