This report reviews the clinical applications of magnetic resonance imaging, (MRI) for the heart and great vessels based on the first 120 patients studied with 1.5 Tesla scanner. Cine scans were obtained in 85% of patients studied with the remainder having T1 spin-echo imaging. MRI provides high-resolution multiplanar images for defining abnormalities in cardiac structure and is especially useful for congenital heart disease. Cine MR evaluates cardiac dynamic functions such as left ventricular volumes and ejection fraction, left ventricular segmental wall motion, and valvular function. It is also useful for detection of aortic and pulmonary arterial disease and diseases of the pericardium. It is concluded that MR has broad applications for diagnosis of cardiac and great-vessel disorders.