Extrinsic compression of the left main coronary artery by an enlarged pulmonary artery is an increasingly recognized and potentially reversible cause of angina and left ventricular dysfunction in patients with pulmonary hypertension. The diagnosis of extrinsic left main coronary artery compression requires a high index of suspicion and should be considered in patients with severe pulmonary hypertension who experience angina. Coronary angiography with intravascular ultrasound is the gold standard for diagnosis of this condition, though cardiac computed tomography and magnetic resonance angiography allow for noninvasive means of screening. The optimal treatment is debatable, but percutaneous coronary intervention appears to be a feasible, safe, and effective treatment option for patients with extrinsic compression of the left main coronary artery from pulmonary artery enlargement. Given the high risk of postoperative right ventricular failure and mortality observed with surgical revascularization in these patients, we recommend that physicians recognize percutaneous coronary intervention as the preferred revascularization strategy for selected patients with extrinsic compression of the left main coronary artery due to pulmonary hypertension. © 2010 Wiley-Liss, Inc.