Aims. In recent years, metabolic syndrome (MS) became a distinct pathological entity. MS is positively associated with cardiovascular mortality. The prevalence of MS is high and a continuing increase is expected. For this reason, all attempts to prevent or manage MS by interventions are extremely important. The new set of definition by International Diabetes Federation (IDF) standardizes criteria for the diagnosis of MS and facilitates its recognition. In a large sample (n = 13 383) of outpatients visiting their general practitioners, we determined the prevalence of risk factors of MS according to the earlier Adult Treatment Panel (ATP) III and the new IDF criteria. Methods and results. The age‐standardized prevalence of MS was 14.9% in males and 8.6% in females (11.5% for all). The most prevalent factors were obesity (ATP III: 38.8% and IDF: 60%) and hypertriglyceridemia (34.1%). Hypertension dominated in men (28.7%), whereas in women obesity was the most prevalent factor (ATP III: 47.4% and IDF: 64%). Conclusion. The prevalence of MS depends on applied definition. The new IDF criteria offer the possibility of focusing on the importance of different components. The real comparison of prevalence among special populations has to be based on age‐standardized data and the use of the same components. In our study, the dominance of obesity, hypertension and hypertriglyceridemia appears to be the major detrimental factors. The 11.5% general prevalence of MS in Hungarians, which means a 25–30% value in the middle‐aged population, needs an urgent preventive approach with lifestyle changes.