On the basis of clinical trials comparing coronary-artery bypass grafting (CABG) with medical therapy, current guideline recommend CABG as the treatment of choice for patients with asymptomatic ischemia, stable angina, or unstable angina/non-ST elevation myocardial infarction who have left main coronary artery disease. Percutaneous coronary intervention can be selectively performed in patients who are candidates for revascularization but who are ineligible for CABG. However, because of advances in periprocedural and postprocedural medical care in patients undergoing either CABG or percutaneous coronary intervention with stenting, new evaluation, and a review of current indications, may be required to determine the standard of care for patients with left main coronary artery disease. Current evidences indicate that stenting results in mortality and morbidity rates that compared favorably with those seen after CABG, suggesting that a current guideline (the Class III recommendation of percutaneous coronary intervention for unprotected left main coronary artery disease) may no longer be justified. Data from several extensive registries and a large clinical trial may have prompted many interventional cardiologists to select percutaneous coronary intervention with stenting as an alternative revascularization strategy for such patients. In addition, these data may inform future guidelines and support the need for well-designed, adequately powered, prospective, randomized trials comparing the 2 revascularization strategies. The cumulative evidence from ongoing and future clinical trials will change the current clinical practice of revascularization for unprotected left main coronary artery disease, which was introduced several decades ago and which has continued to date without major revision.