Plasma insulin, cortisol and somatotropic hormone (STH) levels of coronary patients are related to the extent of atherosclerotic lesion of coronary arteries. The relationship between coronary atherosclerosis and hormonal activity becomes particularly evident through the pattern of hormonal response (a rise or a fall) to rationed exercise. An elevated insulin baseline and reduced postexercise levels are typical for coronary patients with only slightly narrowed (25% or less) coronary arteries. A tendency to higher baseline and postexercise plasma cortisol levels was noted in more severe coronary cases. Increased postexercise plasma STH levels were significantly more frequent in patients with less marked atherosclerotic lesions of coronary arteries.