BACKGROUND/AIMS: A retrospective analysis was performed to evaluate the safety and effectiveness of extracorporeal shock wave lithotripsy (ESWL) for pancreatolithiasis on successive days under intravenous bolus of pethidine alone. METHODS: Ninety patients with calcified pancreatic stones (> or =5 mm) presenting with abdominal pain were selected for ESWL. ESWL was performed with an electroconductive lithotripter under fluoroscopic target systems. Fragmented calculi after ESWL were removed by endotherapy. RESULTS: A mean of 4.2 ESWL sessions were performed for each patient, with a mean of 2,984 shocks at a mean power setting of 12.8 kV. Eighty-four (89.3%) patients underwent ESWL for three or more days in a row. Fragmentation of the stones were achieved in 83/90 (92.2%) patients. Complete clearance of the main pancreatic duct was achieved in 54/90 (60.0%) patients, and partial clearance was achieved in 27 (30.0%) patients. The mean dose of pethidine used during ESWL was 53.5+/-20.7 mg per session. As ESWL-related complications, four (4.3%) patients developed mild acute pancreatitis. CONCLUSIONS: In case of endoscopically difficult-to-treat pancreatic duct stones, combined therapy with ESWL is an effective method, and treatment with multiple sessions of ESWL on successive days under intravenous bolus of pethidine alone is safe and well tolerated.