64 patients (27 men, 37 women; mean age 71 [27-90] years) with intra- or extrahepatic biliary stones, which could not be extracted endoscopically, underwent extracorporeal piezoelectric shock-wave lithotripsy (ESWL). The piezoelectric lithotripter which was used localizes the stones sonographically and the shock-waves are produced by a self-focusing sound generator consisting of 3,000 ceramic elements. The sonographic localization of the stones was successful in 57 patients (89%) and complete removal of stones was achieved in 49 (77%), after an average of 7,595 (1,000-30,800) shock-waves per patient. Spontaneous elimination of stone fragments occurred in 7 patients, while in 42 further endoscopic procedures (balloon catheter, Dormia basket, mechanical lithotripsy) were needed to remove stone fragments from the biliary tract. The only severe complication was cholangitis in two cases. It probably resulted from the associated lysis treatment. There was no case of pancreatitis and no death at 30 days. These data indicate that piezoelectric ESWL with sonographic stone localization is an effective method with few side effects for treating problematic biliary tract stones.