BACKGROUND: Chemoradiotherapy (CRT) is a standard treatment for anal canal cancer although many patients with anal canal cancer undergo surgery in Japan. The efficacy of CRT for anal canal cancer was evaluated retrospectively. METHODS: Medical charts of 13 patients with anal canal cancer treated by definitive CRT from October 2004 to May 2016 were reviewed. Twelve patients had squamous cell carcinoma and one had adeno-squamous carcinoma. PET/CT simulation was performed in nine patients. The median total dose was 59.4 Gy (range 57.6-63.4 Gy) with fractions of 1.8-2.0 Gy. Ten patients received chemotherapy with mitomycin C (10 mg/m2) and fluorouracil (5-FU) (800 mg/m2 over 4 days) in weeks 1 and 5, while two patients were treated with cisplatin (40 mg) and 5-FU (750 mg over 5 days) in weeks 1 and 5. One elderly patient received radiotherapy (RT) alone. RESULTS: All 13 patients were alive after a median follow-up period of 102 months (range 16-121 months). Local failure only occurred in the patient with adeno-squamous cell carcinoma, while there was no loco-regional recurrence or distant metastasis in the other 12 patients. The 5-year loco-regional control rate (LRC) and 5-year overall survival rate (OS) were 92% and 100%, respectively. Acute toxicities of ≥ grade 3 were observed in six patients (46%), mainly being dermatitis around the anal verge, and late toxicity of ≥ grade 3 occurred in one patient. CONCLUSION: CRT for squamous cell carcinoma of the anal canal achieved good LRC and OS with acceptable toxicities.