Diabetes mellitus type 2 (DM2) is one of the most important risk factors for cardiovascular disease. The increasing prevalence worldwide is generating a great health and social concern. Clinical intervention studies such as the UKPDS have shown that although the metabolic control of DM2 may improve with intensive intervention programs, these are highly expensive and do not lead to an optimal metabolic control. For this reason, one of the main challenges in DM2 at present is its prevention. The natural history of DM2 is sufficiently well known and we know that before it is diagnosed, there is a former, often lasting years, "pre-diabetic state" that behaves as a vascular risk factor. In recent years numerous studies have shown that prevention of DM2 is possible. We critically review here the current situation of the disease.