Magnetic Resonance Imaging (MRI) is a new completely noninvasive diagnostic tool available for studying the cardiovascular system. In order to assess its utility in cardiovascular protonic imaging, we studied normal individuals and patients with different heart diseases by means of a 0.5 Tesla superconductive magnet triggered by the ECG. Images were obtained in 38 subjects. By electronically angulating the gradients and by acquiring the images at different phases of the cardiac cycle we obtained several different diagnostic possibilities which can allow both anatomic and functional studies of the heart. On the 21 patients, MRI showed the main features of each disease. Our initial experience with MRI confirms the need for oblique images of the heart in order to obtain planes useful in cardiovascular diagnosis. Among many diagnostic possibilities we tested the ability of MRI in the detection of acute and old myocardial infarction. Although MRI requires extensive application in order to delineate its role in cardiovascular diagnosis it is to be considered an important diagnostic tool and a very interesting investigative method.