Within the wide armamentarium of urinary stone treatment modalities extracorporeal shock wave lithotripsy (ESWL) has been established as the first line procedure. With the Dornier MPL-9000X lithotriptor one has the choice of ultrasound or fluoroscopic localization of calculi throughout the entire urinary tract. Except for the kidney, ultrasound guidance is preferred for calculi in the distal ureter, while fluoroscopy is generally used on the proximal two-thirds of the ureter. Between January and December 1990, 123 ESWL treatments were performed on 83 patients suffering from ureteral calculi with an average stone size of 9.3 x 6 mm. Median treatment parameters were 1,597 shock waves at 19.3 kv. for 43 minutes. For stones in the upper two-thirds of the ureter sedation analgesia was given, while ESWL on the pelvic ureter did not create intolerable pain. Of the treatments 69% were done on an outpatient basis. In situ ESWL treatment of urinary calculi was successful in 72 patients (86.7%), and 20 patients (24.1%) were treated with multiple treatment sessions. ESWL therapy for 47 stones in the distal ureter showed better results than for 33 stones plus 2 steinstrasse in the proximal part (95.5% versus 80% stone-free rate). Of 4 patients with mid ureteral calculi 2 could be rendered stone-free by ESWL alone. Auxiliary procedures, such as percutaneous nephrostomy or ureteral splints, had to be performed in 15.7%. Final endoscopic stone extraction was done in 7 cases and open surgery in 4, constituting a 13.3% failure rate for ESWL therapy. The results prove that the MPL-9000X lithotriptor is effective for primary noninvasive stone treatment.