A 63-year-old man underwent laparoscopic-assisted distal gastrectomy (LADG) and laparoscopic assisted colectomy (LAC) simultaneously for double cancers of the gastric antrum and sigmoid colon in August 2012. Both cancers, considered to be at an early-Stage, were pathologically diagnosed as tub1, sm, and n0. The patient was observed but no adjuvant chemotherapy was administered. A follow-up computed tomography (CT) in December 2012 detected a 15 mm tumor mass in the lateral segment of the liver and another 5mm mass in the S4. Liver metastasis of the sigmoid colon cancer was suspected, and 6 courses of BEV+mFOLFOX6 were administered. The metastatic tumor in the lateral segment showed stable disease (SD) and the S4 tumor showed a complete response (CR). Thereafter, the lateral hepatic segment was partially resected in March 2013. Pathological examinations led to a diagnosis of stomach cancer liver metastasis, and the patient was given oral TS-1. During the first course of treatment, a CT showed new tumor masses in the lateral segment of the liver and S4. Treatment was changed to TS-1+CDDP in mid-May. However, after completion of the first course of treatment, the patient experienced exacerbation of the liver metastases, pulmonary metastasis, and inflammation of the intrahepatic bile ducts. The patient was hospitalized in mid-June to receive inpatient care, but died in early July.