Laser angioplasty has developed as a new method for the treatment of peripheral arterial occlusive disease. In 19 patients with high grade stenoses or obstructions of the superficial femoral, popliteal or posterior tibial arteries (Fontaine stage IIa-IV) percutaneous transluminal laser angioplasty was performed using a novel laser catheter system. The laser catheter itself is made of polyethylene. Its distal tip is formed ovally and marked X-ray densely. A silica fiber (core diameter 0.6 mm) for delivering the laser energy is inserted into the laser catheter. Through a sheath with hemostatic valve, laser catheter and silica fiber are introduced into the artery and then advanced to the stenosis over a guide wire. During laser angioplasty, laser catheter and silica fiber are rotated around the guide wire. We use a cw-Nd: YAG laser with a wavelength of 1064 nm. The mean degree of stenosis decreased from 92 +/- 12% before to 31 +/- 19% after laser angioplasty. By conventional balloon angioplasty a further reduction of the degree of stenosis down to 15 +/- 20% was achieved. The mean systolic Doppler ankle-arm pressure ratio improved from 0.56 +/- 0.25 before laser angioplasty to 0.89 +/- 0.24 after combined laser and balloon angioplasty. In seven patients, clinically non-significant distal embolization occurred. In no patient there was a perforation of the arterial wall. Up to now, digital subtraction angiography 3 months after laser angioplasty has been performed in five patients and showed patency of all lesions. The mean systolic Doppler ankle-arm pressure ratio was 0.84 +/- 0.20.