Pathologic aspects of cardiac aging, and heart diseases as extreme type of aging in the elderly were discussed. 1) Aging of the myocardium: Myocardial hypertrophy does not occur in the normal elderly who do not have heart diseases, most of them ranged between 200 and 350 gm. Amyloid deposit was frequently found in elderly heart (20 to 40%), but cardiac amyloidosis with cardiac symptoms was infrequent (0.2%). 2) Aging of the cardiac valves. Cardiac valves are easily influenced by the mechanical stimuli by incessant valve motion. The circumference of the valves has a tendency to become dilated by aging, especially the aortic valve. Some developed aortic regurgitation. Valvular calcification was marked in the mitral ring, inducing mitral ring calcification, which is found in about 10% of autopsy cases and may cause mitral regurgitation in cases of calcification extending for a length of more than 30 mm. Aortic valves showed calcification in 7% of autopsy cases, causing calcific aortic stenosis in severe cases. 3) Aging of the coronary arteries. The coronary stenotic index was defined as the sum of the highest count of 3 major coronary arteries (point 5 for 100% obstruction, 4 for 75% stenosis and 3 for 50% stenosis etc.). The incidence of myocardial infarction in the group with a stenotic index of more than 9 was markedly higher than in a group with an index of less than 8. 4) Aging of the conduction system. Numeral decrease of conduction cells in the sinoatrial node of the aged was shown by a color image analyzer, which was less severe than cases of sick sinus syndrome.(ABSTRACT TRUNCATED AT 250 WORDS)