Excimer-laser-angioplasty offers the advantage of minimal thermal injury to adjacent tissue compared to other laser ablation techniques. Highly flexible glass-fiber-catheter systems are now available, and are capable of transmitting sufficient energy densities to ablate even calcified atherosclerotic coronary plaques. We report initial results of excimer-laser-ablation of severe coronary stenoses and occlusions in 17 patients. An excimer-laser (308 nm) with a pulse duration of 50 ns and a repetition rate of 10 to 40 Hz served as laser source. Eight patients had a chronic total occlusion (RCA, n = 4, RCx, n = 3, LAD, n = 1), nine patients had 90% to 95% stenoses (LAD, n = 7, RCA, n = 2). In all cases a laser-catheter consisting of 17 circumferentially orientated 100 microns glass-fibers and a central 15/1000-inch lumen could be advanced to the stenoses/occlusion over a guidewire that had been passed across the stenoses/occlusion. Stenoses diameter could be reduced by 41.5 +/- 10.1% in all patients and vessel lumen was further increased by subsequent balloon dilatation in 10 cases. After 24 h, 16 vessels were patent and showed no restenoses; one recanalized RCA was found reoccluded. We observed no complications, such as perforation, spasm, or thrombi.