Because of the interposition of bony structures, extracorporeal shock-wave lithotripsy (ESWL) of middle or iliac ureteral calculi is not feasible in the conventional supine position. By a slight modification of the patient's couch allowing the prone positioning of the patient, 22 patients with calculi covered by bony structures were thus treated. The success rate of 95 percent without complications is promising and renders ESWL therapy as an alternative to ureteroscopic extraction of mid and iliac ureteral calculi.