In a prospective study of 302 ureteroscopic procedures, 161 were commenced and 133 completed without the use of general or regional anaesthesia. In 15 patients ureteroscopy (URS) was performed with lignocaine jelly in the urethra only, and in 118 with additional intravenous analgesia. Alfentanil, a synthetic morphine derivative, was used for intravenous analgesia. Ureteroscopy was performed prior to extracorporeal shock wave lithotripsy in 46 patients, for stone basketing in 40, for stone fragmentation in 29, for diagnostic purposes in 14 and for cold knife ureterotomy in 4. Ureteric lesions were observed in 9 patients (6.8%) treated under intravenous sedoanalgesia. This percentage is within the range reported in other series of patients treated under general anaesthesia. The findings suggest that URS, when performed without general or regional anaesthesia, does not increase the risk of complications or compromise the results of treatment.