Consensus has not been reached about the optimal treatment of type 2 diabetes, and several authors have questioned the use of insulin for this disorder. The reasons are that an association has been found between hyperinsulinaemia and cardiovascular disease in non-diabetic men, and the sparse evidence of a beneficial effect from tight glycaemic control in prevention of late complications in type 2 diabetes. We discuss the pathophysiology of atherosclerosis in type 2 diabetes, and review some of the recent literature. We find it likely that, in the metabolic cardiovascular syndrome found in many patients with type 2 diabetes, insulin resistance is more important than the accompanying hyperinsulinaemia. Furthermore, evidence is emerging of a strong association between hyperglycaemia and atherosclerotic vascular disease in patients with type 2 diabetes. We conclude that insulin treatment should be used in type 2 diabetic patients when the hyperglycaemia cannot be controlled by oral agents.