We evaluated the effectiveness of chemoradiotherapy(CRT)by reviewing 11 clinicalcases of analsquamous cellcarcinoma( SCC). Radiotherapy(RT)consisted of 40 Gy delivered to pelvic and bilateral inguinal lesions, and a perianal booster dose of 20 Gy in fractions of 2.0 Gy per day, 5 days per week. 5-fluorouracil(5-FU)and mitomycin C were administered twice every 4weeks as standard chemotherapy. On the first day of RT, patients received a single bolus dose of 10mg/m2 mitomycin C, and a continuous 24-hour infusion of 750mg/m2 5-FU for 5 days. One patient with a T3 tumor was orally administered S- 1 during RT because of his poor generalcondition, and 1 patient with a T2 tumor did not receive 1 course of 5-FU and MMC owing to an adverse event. Grade 3 adverse effects occurred in 3 patients, but all 11 patients completed CRT. The anal lesions of 10 patients had complete response after CRT. Recurrence of anal lesions occurred in 4 patients, including 2 patients who were not treated with standard CRT. Of 8 patients who received CR via standard CRT, 2 patients had recurrence of anal lesions more than 60 months after completion of CRT. CRT is believed to be safe and effective for improving the prognosis of anal squamous cell carcinoma; however, sufficient and appropriate follow-up is necessary after complete response.