We report a case with perianal squamous cell carcinoma, which showed a complete response more than five years after chemoradiotherapy. A 69-year-old-man was introduced to our hospital for the diagnosis of squamous cell carcinoma [T3 (8.0 × 8.0 cm) N0M0, Stage II]. The patient was treated by chemoradiotherapy, which consisted of 5-FU 750 mg/m²/ day (continuous intravenously) on days 1-5 and 29-33, and mitomycin C 10 mg/m² on days 1 and 29 and radiation at 2 Gy/day for 5 days per week (total dose 60 Gy). The patient tolerated this treatment with no severe adverse effects. Tumor disappeared completely 1 month after this treatment with no adjuvant therapy. The patient has been alive with no sign of recurrence for 6 years.