We evaluated the power of measurements of left ventricular (LV) systolic and diastolic function for predicting exercise capacity in 97 young male survivors of a myocardial infarction. The patients were evaluated with M-mode echocardiography, a symptom-limited exercise test and coronary and LV angiography. In univariate analyses, maximum exercise workload was most closely related to the atrial emptying index, an index of diastolic function (r = 0.37, p < 0.005), but not to LV ejection fraction (r = 0.001, NS). This relationship was stronger in the 42 patients without signs of ischemia during exercise (r = 0.51, p < 0.005). Multivariate analyses indicated that the atrial emptying index (p < 0.005) provided independent contribution to the prediction of maximum exercise capacity. LV diastolic function but not LV systolic function was related to exercise capacity in young survivors of myocardial infarction.