An attempt was made to examine left ventricular wall thickness and wall motion using two-dimensional echocardiography from the acute phase to 1 month after onset of myocardial infarction. Motion abnormalities and thinning of the wall were observed from immediately after the onset. Few areas that were akinetic or dyskinetic and had a wall thickness of 7 mm or less during the acute phase showed improvements in wall motion 1 month later. However, some areas with a wall thickness of 8 mm or more did reveal improved wall motion even if they were akinetic or dyskinetic during the acute phase. Since the akinetic or dyskinetic areas with a wall thickness of 7 mm or less during the acute phase demonstrated a positive correlation with the peak CPK and nQ, and a negative correlation with the left ventricular ejection fraction 1 month after the onset, they were considered to be necrotic zones of myocardial infarction. The area of abnormal wall motion, on the other hand, was considered to correspond to a wider area including the ischemic as well as the necrotic zones. Evaluation of the necrotic and ischemic areas of infarction separately from the acute phase appears to be useful not only for the selection of treatment during the acute phase but also for predicting the cardiac function 1 month later and for determining the time of initiation and method of cardiac rehabilitation.