A strong association between arterial hypertension and Type 2 diabetes mellitus has been known for more than 70 years. However, there are many unanswered questions with regard to the hypothesis of a causal relationship between insulin resistance/hyperinsulinaemia and arterial hypertension. At present, there is no hard evidence for a close (causal) linkage between insulin resistance (or hyperinculinaemia) and arterial hypertension. Currently available antihypertensive drugs in prudent and effective dosages do not result in a deterioration of insulin sensitivity, or in the development of insulin resistance, or an increased incidence of Type 2 diabetes mellitus.