A series of 89 cases of anal carcinoma presenting over a 20-year period is reviewed. The majority were epidermoid carcinomas, 57 arising in the anal canal and 13 at the anal margin. The remainder were melanomas and basal cell carcinomas, and these were not considered further. The main presenting symptoms of epidermoid anal carcinomas were bleeding and pain. Tumours arising in the anal canal were commoner in women whilst those at the margin were more frequent in men. The majority (51/70) had a clinical diagnosis of malignancy made but in 19 cases this was not considered initially. The necessity for routine early histological diagnosis is stressed. Treatment was mainly surgical, either abdominoperineal resection (37 canal, 2 margin) or wide excision (8 canal, 11 margin). The 5 year survival of patients with anal margin tumours was better than those with canal lesions (50 per cent compared with 36 per cent).