Serous cystadenoma of the pancreas is a rare disease and is usually benign. Mucinous cystadenoma, another cystic neoplasm of the pancreas, has a malignant potential. Serous cystadenoma is usually composed of many small cysts lined by small, cuboidal or flattened cells containing abundant glycogen. With the finding of endoscopic retrograde pancreatography, a communication between the cyst and pancreatic duct is observed occasionally in the mucinous cystadenoma, but rarely in the case of serous cystadenoma of the pancreas. We experienced a case of serous cystadenoma of the pancreas that had a communication between a cyst and the pancreatic duct.