Herein, we present a case of advanced rectal cancer surgically resected after chemotherapy. A 65-year-old woman presented with anal pain, and rectal cancer extending beyond the anus was diagnosed. The primary tumor was a well-differentiated adenocarcinoma with a KRAS mutation. Computed tomography revealed cancer invasion into the vagina and sacral and coccygeal bones, and cancer metastases to the bilateral inguinal lymph nodes and the left lung. Sigmoid colostomy and subcutaneous venous port insertion were performed. The patient was treated with modified oxaliplatin, leucovorin, and 5- fluorouracil (FOLFOX6) plus bevacizumab. She showed a partial response according to the Response Evaluation Criteria in Solid Tumors after 13 courses of chemotherapy. The primary tumor was then resected via posterior pelvic exenteration, bilateral inguinal lymphadenectomy, and sacral/coccygeal resection. Histological examination of the resected specimens revealed moderately differentiated adenocarcinoma with vaginal invasion. Metastasis to a right inguinal lymph node was observed. The pathological stage was ypT4bN0M1b, ypStage IV according to the tumor-node-metastasis system of the eighth edition of the Japanese Classification of Colorectal Carcinoma. The pathological response grade of the tumor after chemotherapy was determined to be Grade 1b.