Purpose: Obstructive pancreatic duct stones may cause recurrent acute pancreatitis and chronic abdominal pain. The use of ESWL for treatment of abdominal pain has been well documented; however, its effect on prevention of recurrent acute pancreatitis has not been studied. We evaluated the utility of ESWL for treatment of patients with recurrent acute pancreatitis caused by obstructive stones not amenable to endoscopic removal. Methods: Consecutive patients with recurrent acute pancreatitis due to obstructive pancreatic duct stones not amenable to endoscopic removal were prospectively evaluated. Stones were obstructive if during ERCP the duct proximal (upstream) to the stone could not be opacified by contrast or if opacification could be achieved only under pressure using an inflated extraction balloon. ESWL was performed by a pancreatologist (M.P.) using an electromagnetic shockwave lithotripter (Modulith SLX2, Storz Medical AG, Kreuzlingen, Switzerland). After ESWL, the patients were followed for recurrence of acute pancreatitis. Diagnosis of acute pancreatitis was based on guidelines proposed by the American College of Gastroenterology (Am J Gastroenterol 2006; 101:2379-2400). Results: Ten patients underwent 13 sessions of ESWL (range 1-3). The mean age was 54 years (range 44-72). The cause of chronic pancreatitis was alcohol abuse in 7 and idiopathic in 3 patients. Ductal calcifications were limited to the head of the gland in 4 patients. In 6 patients, the ductal calcifications were more extensive with involvement of the head, body and tail. The mean size of the largest stone in each patient was 1.5 cm (range 1-2 cm). Complete clearance was achieved in 7 (70%) patients. In the remaining 3 (30%) patients, ductal clearance was partial. However, relief of obstruction assessed by post procedure ERCP was achieved in all patients. The mean length of follow-up was 20 months (range 12-36). Three patients had recurrent acute pancreatitis during the follow-up period, caused by recurrence of obstructive stones in two and presence of main duct stricture in one. Conclusion: ESWL of obstructive pancreatic duct stones can prevent further attacks of acute pancreatitis. Recurrence of acute pancreatitis following ESWL may indicate stone recurrence or presence of strictures.