Pancreaticobiliary maljunction(PBM)is frequently associated with biliary cancer due to reflux of pancreatic enzymes into the choledochus,and even after surgery to correct the PBM such patients still have a risk of residual bile duct cancer.Here,we report the case of a 59-year-old female with carcinoma of the papilla of Vater which developed 2.5 years after choledochoduodenostomy for PBM.During the postoperative follow-up period,computed tomography obtained 2 years after the first operation demonstrated a tumor in the distal end of the choledochus,although she did not have jaundice and laboratory tests showed no abnormalities caused by the previous operation.As a result,carcinoma of the papilla of Vater was diagnosed at an early stage,followed by surgical cure.For early detection of periampullary cancer in patients undergoing surgery for PBM,careful long-term follow-up is needed. Pancreaticobiliary maljunction (PBM) is frequently associated with biliary cancer due to reflux of pancreatic enzymes into the choledochus, and even after surgery to correct the PBM such patients still have a risk of residual bile duct cancer. Here, we report the case of a 59 -year-old female with carcinoma of the papilla of Vater which developed 2.5 years after choledochoduodenostomy for PBM.During the postoperative follow-up period, computed tomography obtained 2 years after the first operation demonstrated a tumor in the distal end of the choledochus, although she did not have jaundice and laboratory tests showed no abnormalities caused by the previous operation. As a result, carcinoma of the papilla of Vater was diagnosed at an early stage, followed by surgical cure. For early detection of periampullary cancer in patients undergoing surgery for PBM, careful long-term follow-up is needed.