Extracorporeal shock wave lithotripsy (ESWL not equal to) is the optimal therapy for renal calculi less than 2 cm. in diameter and for proximal ureteral calculi. Controversy continues over the initial approach to distal ureteral calculi (that is below the bony pelvis): in situ ESWL versus ureteroscopy. Since February 1990, 76 distal ureteral calculi were treated at our institution using either in situ ESWL (Dornier HM3 ESWL with a Stryker frame modification in 27 patients or Siemen's Lithostar electromagnetic ESWL in 22) or ureteroscopy (27 patients). Patient age and stone size were similar among the groups. All ESWL treatments were performed with the patient under intravenous sedation and on an outpatient basis. Stone-free rates were 96% for the HM3 device, 84% for the Lithostar and 100% for ureteroscopy. Retreatment was required in 3 Lithostar cases (14%) and 1 HM3 case (4%). When compared to ESWL ureteroscopy for distal ureteral stones was more time-consuming, entailed routine placement of a ureteral stent, often required general anesthesia, more often led to hospitalization and doubled the convalescence period. From a cost standpoint, ESWL on an HM3 unit was a few hundred dollars more expensive than ureteroscopy. In summary, we believe that in situ ESWL provides optimal first line therapy for distal ureteral calculi, while ureteroscopy is better reserved as a salvage procedure should ESWL fail.