In 210 patients with urolithiasis extracorporeal shock wave lithotripsy was performed without regional, general or infiltration anesthesia by means of a technically unmodified Dornier HM3 lithotriptor. The stone burden varied from small ureteral stones to complete staghorn stones. All patients were given premedication with pethidine and diazepam, and a lidocaine-prilocaine-containing cream was applied on the skin at the entry site of the shock wave. Energy usually varied between 14 and 16 kv. More than 90% of the patients reported the pain to be at most of moderate intensity and acceptable. Less than 3% found the treatment unpleasant. The results were compared to those obtained in 250 patients treated with anesthesia according to the original procedure, with a generator voltage of 18 to 23 kv. The number of extracorporeal shock wave lithotripsy sessions for ureteral and large stones was somewhat higher with the low energy method than with the original procedure. However, the therapeutic result in terms of renal units without stones after 4 weeks was similar to that recorded for patients treated with the anesthesia method. According to these promising results we believe that extracorporeal shock wave lithotripsy without anesthesia in an unmodified Dornier HM3 lithotriptor can be performed successfully in a majority of patients and is an attractive alternative to other technical modifications of the equipment.