The use of pulsed dye laser energy for angioplasty offers the possibility of ablating atherosclerotic plaques without thermal damage to the adjacent arterial wall. However, to be of value, systems that deliver the energy safely and effectively are required. We tested multifiber catheters in 504-nm pulsed dye laser angioplasty for treatment of peripheral arterial occlusions. Flexible multifiber catheters consist of 12 (7-French) and 19 (9-French) concentrically arranged 200-microns quartz fibers allowing guidewire-directed use. Laser-assisted angioplasty was performed in 2- to 13-cm- (mean, 7.5-cm) long occlusions of iliac (six) and femoropopliteal (23) arteries in patients with symptomatic occlusive vascular disease. Angiograms were obtained before and after laser ablation, after subsequent balloon dilatation, and if signs or symptoms indicated restenosis, during follow-up. The laser procedure was impossible to perform in three (10%) of 29 patients; this was related to unsuccessful passage of the wire in one patient and to inability to advance the laser catheter across the lesion in two patients. In one other patient, reocclusion occurred 1 day after angioplasty. Stand-alone laser angioplasty relieved residual stenosis of less than 30% in six (26%) of 23 femoropopliteal arteries, making balloon dilatation dispensable. Immediate clinical improvement was achieved in 26 (90%) of 29 patients. Laser treatment caused no perforation and no embolization, but minor dissections occurred in 36% of the patients. Our experience suggests that pulsed dye laser angioplasty via multifiber catheters converts arterial occlusions into stenoses. With the exception of angioplasty in distal femoropopliteal arteries, additional balloon dilatation is necessary to complete recanalization.