A 59-year-old woman underwent surgery for uterine corpus cancer in March 1998. She also underwent pylorus-preserving pancreaticoduodenectomy with pancreaticogastrostomy for common bile duct cancer in November 1998. She was followed up at our outpatient clinic after pylorus-preserving pancreaticoduodenectomy. In November 2002, her carcinoembryonic antigen level became elevated and abdominal ultrasound revealed a huge tumor. Gastroscopy showed a Borrmann type 3 tumor at the anastomosis of the pancreaticogastrostomy, and a biopsy revealed adenocarcinoma. With a diagnosis of advanced gastric cancer, she underwent total gastrectomy, splenectomy, and residual pancreatectomy in January 2003. The pathologic findings revealed that the gastric cancer was separated from the pancreas, suggesting that the cancer had developed from the stomach. The present report describes a rare case of gastric cancer that had developed at the anastomosis of a pancreaticogastrostomy.