Background: The safety and efficacy of left main stenting compared to bypass surgery is still a matter of debate. Use of risk stratification system may be helpful for prediction of periprocedural risk and choice of best treatment strategy. Methods: From April 1997 to February 2006, 565 consecutive patients were treated with left main revascularization using bare metal stent (BMS) (N=67); drug-eluting stent (DES) (N=100), or CABG (N=398). Baseline Euroscore and Parsonnet score were calculated for all patients and cumulative incidence of six-month major adverse cardiac and cerebral events (MACCE) was evaluated. Results: The cumulative incidence of MACCE was significantly higher in BMS when compared to DES (26.9% versus 4.0%, hazard ratio [HR], 0.138, [95% CI, 0.047 to 0.407]; p<0.001) or compared to CABG (26.9% versus 6.5%, HR, 0.229, [95% CI, 0.125 to 0.417]; p<0.001), and it was comparable between DES and CABG (4.0% versus 6.5%, p=NS). On multivariate analysis, Euroscore, Parsonnet score, shock before procedure and left ventricular ejection fraction were independent predictors of MACCE. The cumulative incidence of MACCE of DES was comparable to CABG even in the highest quartile of Euroscore or Parsonnet score (P=NS). Conclusion: DES implantation for left main disease may be feasible and has favorable clinical midterm result not only in low risk subgroup but also in high risk subgroup, if selected carefully. Our results suggest that a randomized study comparing bypass surgery can be justified.