A rare and often fatal condition, total obstruction of the left main coronary artery has been treated with increasing success in both acute and chronic clinical settings. Seventeen patients with acute occlusion have been reported in the literature. All were discovered at the time of acute periinfarction catheterization and were treated aggressively with intracoronary thrombolysis, percutaneous transluminal angioplasty, emergency bypass surgery, or a combination of techniques. Chronic total occlusion of the left main coronary artery has been reported in 59 patients, including 3 at our institution. These patients present with chronic but increasingly severe angina. A right dominant coronary anatomy is always found, usually with well-developed right-to-left collaterals. The results of surgical revascularization in our 3 patients and in 45 others described in the literature support the safety and efficacy of this approach.