This is the first description of severe acute pancreatitis in pancreas divisum caused by a solitary stone impacted in the minor papilla. Recovery was rapid after diagnostic endoscopic retrograde cholangiopancreaticography (ERCP) and endoscopic stone removal. Since other etiological factors accounting for the acute pancreatitis were carefully excluded, it seems that obstruction of the minor papilla by a solitary pancreatic concrement was the most likely cause of acute pancreatitis. This case report demonstrates the diagnostic importance of early ERCP in cases of etiologically unexplained acute pancreatitis.