A 35-year-old man was hospitalized for severe acute pancreatitis. On the 24th hospital day, CT scan showed a pancreatic pseudocyst in the head of the pancreas. Conservative medical treatment for 1 month was not effective, and CT scan revealed a fistulous communication of the pseudocyst to the common bile duct and duodenum. After the formation of a fistulous communication, we detected common bile duct stones composed of fatty acid calcium and we removed them endoscopically. The pseudocyst gradually decreased in size and disappeared 4 months later. Follow-up CT scan showed no sign of recurrence.