Anal cancer is a rare clinical entity which represents 1-2% of all gastrointestinal tract cancers. Due to the paucity of this malignancy it has been difficult to establish generally accepted guidelines for treatment, although various therapy modalities have been evaluated. For a long time radical surgery was the primary treatment for anal cancer and still about 30% of the patients undergo abdominoperineal rectotomy. However, recurrence rates of 20-40% have been observed after this mutilating procedure. Therefore, other treatment options, including external or interstitial radiotherapy and chemotherapy, are used increasingly with the intention to preserve sphincter function. In the last years much interest has been addressed to multimodal therapy with radiation (50 Gy) and chemotherapy (5-fluorouracil and mitomycin C). Presently radiochemotherapy appears to be the most efficient therapy in advanced anal cancer. Locoregional tumor control is obtained in 60-80% of the patients and there is evidence that radiochemotherapy can improve disease-free survival. Despite considerable toxicity, radiochemotherapy should be recommended as primary therapy to most patients.