Background. Since its introduction in 1974 ES has become the treatment of choice for CBDS in cholecystectomized and elderly patients unfit for surgery.With further experience, ES has been widely applied also in young and fit patients. Recently, three significant factors for late complications after ES for CBDS were identified (Pereira-Lima 1998): 1) peripapillary diverticulum (recurrence of CBDS); 2) gallbladder in situ (recurrence of biliary symptoms); 3) common bile duct (CBD) diameter ≥ 15 mm (recurrence of CBDS and/or biliary symptoms). Aim of this study was to evaluate the long-term clinical outcome of ES for CBDS, and identify patients at risk for recurrence in a selected group with a follow-up of at least 5-years. Materials and methods. 529 patients (296 females, 233 males, mean age 62 years range 9-88) that underwent successful ES+CBDS extraction between april 1983 and december 1993 were included in the study. Followup data were obtained from our patient records, by mail, telephone call, interview, or ERCP when indicated. The following parameters have been included in statistical analyses: sex, age, gallbladder status, previous biliary tract surgery, prior gastrectomy, clinical presentation, ES-related complications, precut, stone size, number of stones, CBD diameter, duodenal diverticulum, infundibular fistula and liver function tests. Asymptomatic patients with follow-up < 5 years and patients who died for unrelated diseases before a 5-year follow-up period were excluded from statistical analyses. Results. Complete follow-up data were available in 430 patients (81.3%): 280 (65.1%) were asymptomatic; 99 (23%) died from unrelated causes without symptoms recurrence; one died from acute cholangitis; 50 (11.7%) had recurrence of CBDS and/or biliary symptoms. Statistical analyses included 334 patients with a mean follow-up of 7.5 years (range 0.1-15). Uni- and multivariate statistical analyses proved that a dilated CBD (i.e., ≥22 mm) is the only risk factor (RR= 1.06; 95% CI= 1.01 -1.12; p= 0.029) for CBDS and/or biliary symptoms recurrence in our series. Conclusions. ES for CBDS is a safe and effective treatment even in the long-term follow-up. Definitive treatment is provided in more than 85% of patients. According to our data the risk of recurrence of CBDS and/or biliary symptoms is increased in patients with enlarged CBD (diameter ≥ 22 mm).