Hyperamylasaemia and acute pancreatitis are the more common complications of endoscopic retrograde cholangiopancreatography (ERCP). Ninety patients who underwent ERCP +/- endoscopic papillotomy were monitored for rises in the serum amylase and the development of acute pancreatitis. The incidence of hyperamylasaemia (greater than 300 IU/L) was significantly greater (p = 0.01) when the pancreatic duct was imaged (75%) than with bile duct imaging alone (33%). The incidence of acute pancreatitis following imaging of the pancreatic duct +/- bile duct was 11.3% and was found to be significantly increased in those patients (n = 9) who also underwent endoscopic papillotomy. Imaging of the biliary tree only +/- endoscopic papillotomy carried no significant risk of acute pancreatitis. In those patients who developed pancreatitis, the rise in serum amylase occurred early and was significantly higher at 2 h following ERCP. These findings may help to identify patients who are at risk of developing this complication.