Unprotected left main coronary artery (ULMCA) angioplasty has been considered to be contraindicated. Recent studies suggest that new devices improved its results with relatively small number of patients and short-term follow-up. We analyzed our data of ULMCA angioplasty and evaluated its feasibility and effectiveness.Methods: Between 286 to 897, consecutive 145 procedures in 94 patients with ULMCA stenosis were performed electively. There were 82% male and 40% restenosis cases. Final treatments were directional atherectomy (DCA) (50%), balloon angioplasty (41%), and stents (8%). There were 29% three vessel diseases, 19% heart failure and/or unstable angina, 32% age =<75, 65% prior MI, 6% prior CABG, and 22% EF =< 35% cases. Follow-up angiography was scheduled at 1 day and at 3, 6, and 12 months after angioplasty.Results: 1) Initial results: ULMCA stenoses of 140 cases (97%) were improved to =<50%. There were 2 (1.4%) cardiac death, 3 (2.1%) non-cardiac death, 2 (1.4%) QMI, 7 (4.8%) non-QMI, 10 (6.9%) repeat angioplasty, and 0 (0%) CABG. 2) Restenosis rate: Restenosis rate was 35.2% within 3 months, and 47.0% within 1 year. The restenosis rate of DCA was 26.3% and lower than that of balloon angioplasty (63.2%, p < 0.0005) and that of stents (44.4%, p = NS). 3) Long-term results of 94pts: Mean follow-up period was 2.8 years. Three-year survival rate was 80.6%, and 3-year cardiac survival rate was 90.0%.Conclusions: ULMCA angioplasty is feasible and effective under scheduled angiographic follow-up. DCA is promising procedure for ULMCA stenosis because of its lower restenosis rate.