We report the case of a patient with ampullary carcinoma, diagnosed as having liver metastases by staging laparoscopy, who underwent subsequent laparoscopic biliary bypass during the same operation. A 61-year-old man with jaundice was found to have ampullary carcinoma on CT and ERCP. However, no metastatic lesions were detected on FDG-PET, and we decided to perform laparoscopic pancreaticoduodenectomy. After 1 month of bile drainage and control of cholangitis, we performed a preoperative CT scan that indicated the presence of multiple small low-density areas in the liver. However, it was difficult to distinguish whether the hepatic lesions were metastases or inflammatory changes. Therefore, we decided to choose the operative approach based on the findings obtained from staging laparoscopy. During the procedure, small nodules were observed on the liver surface and were resected. As the resected specimens were found to be adenocarcinomas on pathological examination, we performed Roux-en-Y laparoscopic hepaticojejunostomy using running 4-0 PDS sutures. The postoperative course was uneventful and the patient was discharged on postoperative day 18, after the introduction of systemic chemotherapy. Laparoscopic biliary bypass followed by staging laparoscopy is among the useful methods for unresectable peripancreatic malignancies.