In the last few years the treatment of urinary calculi has been dramatically transformed by new endoscopic methods and extracorporeal shock wave lithotripsy. Laser lithotripsy is in keeping with this evolution. After a short description of the principle of laser lithotripsy, a prototype pulsed dye laser lithotriptor, developed by the Centre d'applications laser, Ecole polytechnique federale de Lausanne, is presented. This device is compared with other lasers proposed for the same application.