From November 1997 to May 1998, 295 patients with a single renal or upper ureteral radioopaque stone of less than 2 cm. were treated with the Doli 50 lithotriptor (Dornier Medical Systems, Marietta, Georgia). The treating anesthesiologist and patient together elected intravenous sedation or general anesthesia. Of the 92 patients 60 (65%) treated under intravenous sedation and 126 of the 203 (62%) treated under general anesthesia had 3-month followup records available for review. Extracorporeal shockwave lithotripsy was considered a failure if residual stone fragments remained after 3 months, or an auxiliary procedure or re-treatment was required.