A new ultrasound lithotriptor in the treatment of bladder calculi is presented. This apparatus simultaneously allows the litholapaxyof the stones under direct observation and suctioning out of the fragments. In this process, the movable ultrasound probe is of considerable advantage. The technique was used successfully in the treatment of 20 patients with a total of 67 larger-than-cherry-size bladder stones. No risks or complications have been observed.