Percutaneous transluminal laser angioplasty of the peripheral arteries was performed in 16 patients with pain at rest, objective evidence of severe peripheral ischemia, conditions requiring amputation, and/or medical contraindications to surgery. In 14 patients the ipsilateral femoral artery was entered in an antegrade direction using the Seldinger technique, base-line angiograms taken, and laser angioplasty performed using argon ions transported to the target site by a 400-mu quartz fiber. Patency was established in 50% of cases and correlated directly with both total energy delivered and time and power per exposure: the lower the energy, the higher the patency rate. Complications included spasm, pain, and mechanical or laser perforation. The authors conclude that while percutaneous transluminal laser angioplasty of peripheral arteries using argon radiation is possible in man, its clinical value has not been established.