Background: Currently, cholecystectomy is recommended for patients with gallstone-induced pancreatitis. ERCP with endoscopic sphincterotomy (ES) within 24 to 48 hours is also suggested for the treatment of acute gallstone pancreatitis. The aim of this study was to determine outcome after cholecystectomy versus ES alone in patients with gallstone pancreatitis. Methods: One hundred seventeen patients with gallstone pancreatitis were included in this prospective observational study. Inclusion criteria were typical abdominal pain; serum amylase level 3 times or greater than normal; and gallbladder stones and a dilated bile duct, with or without stones, by US, CT, or ERCP. Results: Eighty-three patients (Group A) underwent cholecystectomy after initial evaluation including ERCP in 43 (53%) and ERCP with ES in 38 (47%). The remaining 34 (Group B) underwent successful ERCP with ES alone. Mean follow-up was 33 months for Group A and 34 months for Group B. Recurrent gallstone pancreatitis was noted in 2 patients (2.4%) in Group A (bile duct stone in 2, sludge and papillary stenosis in 1), and in 1 patient (2.9%) in Group B. Ten patients in Group B had follow-up US of the gallbladder that showed disappearance of stones in 3. During follow-up, there was no significant difference in the rates of biliary complications (Group A, 3.6% vs. Group B, 11.6%; p = 0.19) or serious complications (pancreatitis, cholecystitis, cholangitis) (Group A, 3.6% vs. Group B, 5.8%). Also, there was no significant difference in procedure-related complications. Conclusions: Recurrence of pancreatitis after ERCP with ES alone for gallstone pancreatitis is rare. In patients who have undergone ES alone, cholecystectomy should be considered only if there are overt manifestations of gallbladder disease (e.g., biliary pain, cholecystitis, cystic duct obstruction) and not for prevention of recurrent gallstone pancreatitis. Because treatment by ES alone may be associated with a higher risk of biliary complications during follow-up compared with cholecystectomy, these patients may require close surveillance. (Gastrointest Endosc 2002;56:61-5.)