We reported an elderly case of squamous cell carcinoma of the anal canal which showed complete response following radiotherapy alone. An 86-year-old man complaining of anal bleeding and pain was admitted. Colonoscopy showed a type 1 tumor just above the dentate line. Biopsy revealed squamous cell carcinoma. Serum SCC Level before treatment was elevated (8.4 ng/mL). Magnetic resonance imaging did not show any metastatic lesions. Since the patient and his family members refused a surgical intervension and chemotherapy, he received an external radiotherapy (total dose: 60 Gy) to the pelvic space and showed complete response after radiotherapy. He is alive without evidence of recurrence about three years after the radiation, although serum SCC is slightly elevated.