The insulin resistance/metabolic syndrome is characterized by the variable co-existence of hyperinsulinemia, obesity, dyslipidemia (small dense low-density lipoprotein, hypertriglyceridemia, and decreased high-density lipoprotein cholesterol), and hypertension. The pathogenesis of the syndrome has multiple origins. However, obesity and sedentary lifestyle coupled with diet and still largely unknown genetic factors clearly interact to produce the syndrome. This multifactorial and complex trait of metabolic syndrome leads to increased risk of cardiovascular disease. The scope of this review is to examine the differences in prevalence of the metabolic syndrome in various groups (eg, according to age, sex, ethnicity, social status, or presence of obesity) that could help with the better understanding of the pathogenesis of this syndrome. This review also considers the impact of metabolic syndrome on cardiovascular disease.