Although insulin-dependent and non insulin-dependent diabetes mellitus have a different pathogenesis, they are often indistinguishable by clinical and laboratory parameters. Complications in connection with diabetic micro- and macroangiopathy (retino-, nephro- and polyneuropathy, cardiovascular risks) are similar in both types of diabetes. Treatment is based on clinical presentation and routine laboratory tests, its goal is normoglycemia. The criteria for use of insulin are the same for all variants of diabetes. Control of associated cardiovascular risk factors is decisive. Diabetes is a clinical syndrome.