ABSTRACT Mitral valve surgery has become an increasingly common procedure for patients with mitral valve disease. Iatrogenic coronary artery lesion has been reported as an uncommon and potentially fatal complication of mitral valve surgery. Its diagnosis must be considered during perioperative care, and coronary angiography helps in deciding the best therapeutic strategy. In the present clinical report, we describe a patient with iatrogenic occlusion of the left circumflex artery after surgery for mitral valve replacement due to rheumatic disease.