The patient was a 78-year-old woman with a chief complaint of abdominal bloating and constipation who was referred to us and was examined for an AV 12-15 cm, circumferential type 2 rectal cancer. The pathological diagnosis was adenocarcinoma (tub1+tub2). T4 and N2 were suspected based on the CT findings, and because the CEA value was high, the patient was treated with 7 courses of mFOLFOX6 neoadjuvant chemotherapy followed by salvage surgery(low anterior resection+D3). Examination of the surgical specimen revealed chronic inflammatory cell infiltration, including histiocytes accompanied by ulceration, and fibrosis was observed down to SS. No viable cancer cells were detected, and the tumor response was evaluated as a pathological CR. mFOLFOX6 appeared to be effective as neoadjuvant chemotherapy for advanced rectal cancer.