Anomalous left coronary artery from the pulmonary artery (ALCAPA) is a rare congenital anomaly that usually manifests in childhood and has a high mortality rate in the first year of life if not corrected. We present the case of a middle-aged woman who presented with exertional dyspnea and severe ischemic mitral regurgitation; further imaging revealed it was secondary to ALCAPA. The patient was referred for valvular reconstruction and surgical revascularization with left coronary artery reimplantation in the aorta. The patient had an adequate postoperative result and symptomatic improvement during follow-up. Although ALCAPA is a rare cause of mitral regurgitation in adults, its pathophysiology is like that of ischemic origin from atherosclerotic coronary disease, and its treatment is therefore similar to obtain adequate clinical improvement.