To evaluate left ventricular diastolic function in patients with coronary artery disease, gate radionuclide ventriculography was performed prospectively in 42 patients who were admitted to Seoul National University Hospital from November 1985 to August 1986 because of anterior chest pain. All patients had no valvular heart disease, congenital heart disease, cardiomyopathy and arrhythmia, and no abnormal vall motion in gated nuclide ventriculography and contrast left ventriculography. 25 patients with more than 50% of stenosis in coronary arteriography were compared with 17 control subjects without stenosis. The following results were obtained; 1) There were no significant differences between normal controls and patients with coronary artery disease in the analysis of the parameters of the left ventricular systolic function, such as ejection fraction (EF), peak ejection rate (PER), time to peak ejection rate (TPER) and ejection time (TES, TES/BCL). 2) Same results were found with those of the left vnetricular diastolic function, such as peak filling rate (PFR), diastolic time interval (DTI, DTI/BCL), rapid diastolic filling interval and time to late diastolic filling (TLDF). 3) The percent contribution of late diastolic filling to stroke volume (%LDF/SV) was more increased in patients with coronary artery disease than the normal control subjects (38.2+/-12.4% vs 28.3+/-7.8%, P<0.01). 4) As the results of above, it can be concluded that the percent contribution of late diastolic filling to stroke volume (%LDF/SV) obtained by using the non-invasive method of gated radionuclide ventriculography can be a sensitive parameter for early evaluation of the left ventricular diastolic dysfunction in coronary artery disease.