Transurethal laser prostatectomy, using a 600-(mu) laser quartz fiber capable of directing the laser energy at 90 degree(s), a neodymium: YAG laser, and conventional cystoscopic equipment was satisfactorily performed in dogs. Urinary continence was preserved. Preliminary studies suggested an optimum power setting of 60 W delivered for 60 seconds at four quadrants (12, 3, 6, and 9 o'clock positions). In these animals, the technique provided a simple and safe procedure and did not require catheter drainage.