Lithotripsy with the pulsed-dye laser has been shown to be a safe and effective method of intracorporeal urinary stone fragmentation. Recently, a new device, the holmium: YAG laser, has been developed with both soft tissue and lithotripsy applications. We present our preliminary experience with the Ho:YAG laser for lithotripsy of urinary calculi. Ureteroscopy and lasertripsy resulted in successful fragmentation of ureteral stones in 92% of 21 patients when the laser was used alone or in combination with electrohydraulic lithotripsy. One complication directly related to the use of the laser occurred, a ureteral perforation, when the device was utilized under fluoroscopic control. In four patients undergoing percutaneous flexible nephrolithotripsy, the laser demonstrated utility in fragmenting caliceal stones remote from the nephrostomy tract. In summary, the Ho:YAG laser has demonstrated its efficacy as a method of intracorporeal lithotripsy. The tissue effects of this device, as well as the optimal energy/pulse and frequency settings, need further evaluation in order to minimize the risks of tissue injury.