Extracorporeal shock wave lithotripsy (ESWL) currently is performed in selected urologic centers to treat over 80 per cent of patients with symptomatic upper urinary tract calculi. This noninvasive technique utilizing shockwaves to disintegrate stones into sand-sized particles allows the patient to pass the particles with spontaneous urination and replaces most surgery or percutaneous endoscopy for stone removal. However, stone-free success rates must be individualized depending on stone position, stone size, and composition. Lithotripsy of renal stones prior to migration and proximal ureteral stones early in their symptomatic course may alter significantly the incidence of distal ureteral calculi requiring hospitalization, cystoscopy, or ureteroscopy.