The authors describe their initial experience with examination of the heart by magnetic resonance (MR) and discuss its position in the diagnostic algorithm of cardiac examinations:. They made 31 MR examinations of the heart in 30 patients. Echocardiography preceded 29 examinations. MR proved to be particularly useful where echocardiography did not lead to a decisive conclusion and called for confirmation by another method, or where it could not be carried out or its result was not consistent with the patient's clinical condition or the results of other examinations. The quality of the MR image was influenced most by the possibility of ECG gating. The latter was not possible in 16 patients (51.6%). In three of these (18.8%) the images were of such poor quality that they did not provide adequate diagnostic information. Images suitable for evaluation were obtained in 28 examinations (90.3%)--in these patients the MR information was valuable for establishment of the diagnosis. Magnetic resonance is a new possible method in the non-invasive diagnosis of heart disease. In the majority of cases it follows after echocardiographic examination which remains due to its accessibility the basic non-invasive method for examination of the heart.