In order to find the relationship between insulin resistance and angiotensin II and endothelins in patients with essential hypertension and coronary heart disease, blood glucose and insulin were measured during OGTT. Their area under the curve were also calculated. Fasting angiotensin II and endothelins were measured in 35 patients with essential hypertension. 32 patients with coronary heart disease and 20 healthy subjects. The results revealed that both the patients with essential hypertension and coronary heart disease were insulin resistant. Insulin resistance was higher in essential hypertension than in coronary heart disease. The group with essential hypertension showed higher insulin concentration at 1 hour postload and also greater total secretion of insulin. In the two groups of patients, both the insulin level during OGTT and the area of insulin were significantly positively correlated with angiotensin II level. In patients with essential hypertension, the level of endothelins was positively correlated, with insulin level at 1 hour postload and the area of insulin. It is suggested that the interaction between insulin resistance and angiotensin II and endothelins might be involved in the development of essential hypertension and coronary heart disease.