Using the new Dornier lithotriptor MPL 9000* (multi-purpose lithotriptor) 381 treatments of urinary stones were performed from July 1988 to December 1989, 107 (28%) of them for ureteral calculi. Sonography enables stone localisation even in many cases where positioning by conventional x-ray fluoroscopy would not be possible. In 20 cases of upper ureteral stones, localization had to be performed partly by indirect measures, i.e. at the end of the dilated ureter. In 10 ureteral stones of the middle third sonographic positioning and complete disintegration was achieved. Treatment was without anaesthesia and was performed in a comfortable supine position. Therapy of 77 ureteral calculi in the caudal part--without anaesthesia--has proved extremely successful. Since it is less invasive than other measures (e.g. uretero-renoscopy or loop extraction), it is now the method of choice for the treatment of stones in the middle and lower third of the ureter.