In contrast to the majority of renal calculi, in situ extracorporeal shock wave lithotripsy (ESWL) for upper ureteral stones is still controversial. Some centers recommend retrograde mobilization of the calculus into the renal pelvis prior to ESWL as a routine procedure (UC + ESWL). To evaluate the efficiency of in situ ESWL for upper ureteric stones, we initiated a prospective clinical trial. From July 1985 to January 1986, 122 patients presented with upper ureteral calculi, necessitating a total of 146 different procedures: 88 in situ ESWL; 31 UC + ESWL;15 antegrade ureteroscopies (URS); 6 retrograde URS; 2 open surgery (ureterolithotomy, nephrectomy), and 4 patients were managed conservatively. Of all 99 patients treated at the lithotripter, 80 patients received in situ ESWL(no emergency case, no location problems): in 60 patients (75%) the stone could be disintegrated in one session; 8 patients (10%) required a second ESWL session due to partial fragmentation. Retrograde mobilization using a ureteral catheter or URS was necessary in 9 patients due to failure of in situ ESWL (11 %) and, in only 3 patients, we had to remove the stone by antegrade URS (4%). In conclusion, 96% of all upper ureteric stones suitable for primary ESWL could be treated by a noninvasive (in situ ESWL) or minimally invasive (UC + ESWL) procedure. Therefore we recommend in situ ESWL for these calculi. Primary retrograde mobilization is only indicated in case of location problems (stone close to the spine, obesity, skeleton deformation) or emergency cases (colic, hydronephrosis). Antegrade URS should be performed if retrograde mobilization fails or in emergency cases (acute pyelonephritis, following percutaneous nephrostomy, after clinical stabilization). The rate of open surgery is below 2 %.