The more and more exact and simple determination of insulin provides an opportunity for exploration of the states of insulin resistance. It turned out hereby that the so-called type 1 diabetes is merely a consequence of insulin deficiency and it occurs mainly in the young. In contrary, the so-called type 2 diabetes is a multifactorial, often hyperinsulinaemic condition of insulin resistance and it occurs mainly in the adults. Furthermore, the epidemiological observations of the last decades elucidated that insulin resistance and compensating hyperinsulinaemia are common not only in type 2 diabetes but in other conditions as in ischaemic vascular diseases, hypertension, obesity, lipid alterations, coagulation disturbances, too. It became evident that the so-called late vascular complications of diabetes mellitus may develop before or without the existance of any disturbances in carbohydrate metabolism. These facts encouraged the recognition of metabolic syndrome-X. According to this hypothesis, insulin resistance and compensatorial hyperinsulinaemia are the causes of atherosclerosis, hypertension, upper body obesity, dyslipidaemia, type 2 diabetes and disturbances of coagulation. Following the last years, it became evident that hyperuricaemia, microalbuminuria and even type A personality are common in this syndrome of insulin resistance.