The therapeutic results of extracorporeal shock wave lithotripsy (SWL) for distal ureteral stones were compared between 70 patients treated without a ureteral catheter (Group 0) and 142 patients treated during a period when attempts always were made to pass the stone with a catheter before the treatment (Group UC). All SWL procedures were carried out with an unmodified Dornier HM3 lithotripter and with only analgosedation with pethidine (meperidine) and diazepam. One shock wave session was sufficient in 76% of the patients in Group 0 and in 77% of those in Group UC. There were no differences between the groups in terms of need for retreatment and the mean numbers of sessions were 1.37 +/- 0.79 (SD) in Group 0 and 1.28 +/- 0.61 in Group UC (P > 0.05). The stone-free rate after 4 weeks was 96% and 97%, respectively. This result was achieved without ureteral manipulations after SWL in 89% of the patients in Group 0 and in 95% of the patients in Group UC (P > 0.05). The number of shock waves and the energy index were lower in Group 0 than in Group UC (P < 0.001). Patients with distal ureteral stones apparently can be treated with SWL without a ureteral catheter with approximately the same success rate as with a catheter. The use of a catheter might, however, be of value for easy localization of scarcely radiopaque stones and possibly in some cases of seriously impacted stones, as well as for treatment of children, who regularly require general anesthesia.