We have successfully used a balloon-guided laser to ablate arteriosclerotic plaque, thus permitting use of standard angioplasty to treat seven patients with severe peripheral artery obstruction. The device (Lastac System, marketed by G.V. Medical, Inc, and approved by FDA in December 1988) is designed to reduce the incidence of vessel perforation by using the balloon to center an argon laser between the vessel walls. A control monitor allows the physician to determine the amount and duration of energy applied. A lens on the laser tip further reduces risk of damage by narrowing the laser beam's angle of delivery, and an infusion pump cools tissue receiving laser energy and clears blood from the beam's field. Each of the seven patients treated with the Lastac System continues to be free of claudication; one patient experienced clinically insignificant vessel perforation. Although this series of patients is quite small, we believe increased use of the system will further demonstrate its effectiveness in eliminating plaque and probably will reduce the occurrence of restenosis.