Although first knowledge on the joint onset of cardiovascular risk factors had been gained earlier, the first systematic review of this condition was made by G. Reaven in 1988 with his thesis on syndrome X, today known as the metabolic syndrome, with insulin resistance as the common denominator. Four elements have been identified: central obesity, dyslipoproteinemia (increased triglycerides, reduced HDL cholesterol), hypertension and glucose intolerance. There are two most influential definitions: one by the National Cholesterol Education Program (NCEP) and the other by the International Diabetes Federation (/IDF). NCEP requires the presence of at least three of the following factors: abdominal obesity as assessed by waist circumference >102 cm (m) or >88 cm (f), dyslipoproteinemia defined as triglyceridemia > or =1.7 mmol/L and/or HDL cholesterol <1.03 mmol/L (m); <1.29 mmol/L (f), hypertension (blood pressure > or =30/85 mmHg) and fasting glycemia > or =5.6 mmol/L (previously 6.1). IDF focuses on central obesity defined as waist circumference, taking into consideration sex and ethnic group specificities, with the presence of at least two additional factors (dyslipoproteinemia, hypertension, or increased fasting glycemia - all criteria virtually the same as in NCEP definition). Both IDF and NCEP define abdominal obesity by waist circumference, taking account of sex differences, and, in case of IDF, ethnic ones as well. The idea is to identify the simplest measure to indirectly determine the accumulation of visceral fat, which is, contrary to subcutaneous fat, a significant cardiovascular risk factor. However, waist circumference as the only criterion seems to be less specific than the waist-to-hip circumference ratio, which defines the risk more specifically and also better reflects insulin resistance. There is broad discussion as to whether the term metabolic syndrome contributes to the identification of persons at risk of cardiovascular disease better than its components, and, if so, which is the right set of components. It is being recommended that the discussion on the metabolic syndrome be limited to persons without diabetes or already diagnosed cardiovascular disease, as the primary goal for these individuals is to prevent these diseases. It has already been shown that this was possible, primarily by intensive change in lifestyle - healthy diet and exercise. In conclusion, further basic research is necessary to explain the pathophysiologic mechanisms, which might serve to develop new therapies. Moreover, epidemiological and public health aspects are extremely important in the creation of a prevention program. Preliminary results of the Croatian Health Survey (2003) indicate that the metabolic syndrome according to the IDF criteria is present even in the youngest age group, with expected age-dependent increase in both men and women. This is even an underestimate since in this survey only blood pressure and waist circumference were actually measured, and data on dislipidemia and blood glucose were based on a questionnaire. It is already obvious that a wide action with two main goals aimed primarily at the youngest population is necessary: an increase in regular physical activity and the promotion of healthy and energy-adequate diet in the population at large.