A 60-year-old man presented with anal pain. He was diagnosed as having perianal abscess and carcinoma associated with anal fistula. We performed chemoradiotherapy (radiation, total 50.4 Gy; capecitabine 2,000 mg/m2) followed by chemotherapy( XELOX, 2 courses: capecitabine 2,000 mg/m2, oxaliplatin 130 mg/m2). After chemoradiotherapy, the tumor significantly reduced in size. Laparoscopic abdominoperineal resection of the rectum, extended resection of the perianal region, and reconstruction of the perianal skin defect using a rectus abdominis musculocutaneous flap were performed. Histopathologically, the tumor was classified as tub2, pMP, ly0, v0, pN0 (0/3), pStage I, and the therapeutic efficacy was classified as Grade 2. Chemoradiation appears to be effective for the treatment of carcinomas associated with anal fistula.