In order to determine the validity of the left ventricular (LV) diastolic function for evaluation of ischemic heart disease, gated radionuclide angiography was performed in 37 patients with transmural myocardial infarction (MI) [18: anterior, 19: inferior infarction] and 10 normal control subjects. LV ejection fraction (LVEF) was decreased in patients with anterior MI but not in those with inferior MI. Time to peak filling rate was not significantly prolonged in both anterior MI and inferior MI. Filling fraction was apparently reduced only in anterior MI. However, peak filling rate (PFR) was significantly reduced even in inferior MI as well as in anterior MI. PFR correlated well with LVEF in normal control, anterior MI and inferior MI. In both anterior MI and inferior MI, their coefficients were smaller than in controls. The normal PFR always indicated normal LVEF, while normal LVEF was not necessarily indicative of normal PFR. Results indicated that LV diastolic function estimated by equilibrium radionuclide angiography might reflect more precisely LV dysfunction in old MI than LV systolic function. The reduction of LV diastolic function in old MI was more prominent than that of LV systolic function. Therefore, it may be deduced that evaluation of LV diastolic function is essential to the estimation of the degree of ischemic myocardial cell damage and the efficacy of drugs on ischemia-induced LV dysfunction.