PURPOSE: The incidence of unhealed chronic fistula is about 7% and the cancer can occur in the longstanding unhealed fistula. The most of the cancer is mucinous adenocarcinoma. The report is diverse about treatment, adjuvant chemotherapy and prognosis. The purpose of this study is review of the clinical characteristics and survival of the anal cancer arising from chronic fistula-in-ano. METHODS: The number of patients was 10. The diagnosis is made under pathological examination at the Kanbuk Samsung Hospital from 1983 to 2000. The retrograde study was done with patients' records and telephone questionnaire. The survival rate was calculated with Kaplan-Meier method. RESULTS: All patients were male. The patients had symptoms of anal discharge and anal swelling suggesting the anal fistula. The patients had history of anal surgery. The external openings were multiple. Seven patients had mucinous adenocarcinoma. The prognosis was poor. Among 8 patients' follow-up data, except one patient, 7 patients died within 43 months. CONCLUSIONS: The anal cancer can occur in longstanding unhealed fistula. In our series, all patients were male, and they had multiple opening fistula. The patient who had small size tumor have only survived. Through meticulous exploring and deep biopsy of the fistula, early detection is best method to treat the anal cancer arising from chronic fistula-in-ano.