Background. Ostial stenosis of the left main coronary artery is a serious condition with a dismal prognosis. The treatment is surgical, with the two viable options being coronary artery bypass grafting and surgical angioplasty of the left main coronary artery. Methods. We describe the use of surgical angioplasty to treat 3 patients (2 women and 1 man) with left main ostial stenosis using the posterior approach. Patency of the angioplasty was demonstrated subsequently with magnetic resonance imaging. Results. All 3 patients were free of angina 12, 18, and 24 months after operation. Magnetic resonance imaging scans in all 3 patients demonstrated the widely patent left main coronary artery. Conclusions. Surgical angioplasty is an effective alternative to coronary artery bypass grafting in patients with left main ostial stenosis. Magnetic resonance imaging is an excellent noninvasive method for monitoring the patency of the left main coronary artery.