The concept of the metabolic syndrome has now been in existence for several decades; however, it has only been since some agreement on definitions of the syndrome was reached that it has been possible to compare the prevalence among populations worldwide. Just as the prevalence of the individual components of the syndrome varies among populations, so does the prevalence of the metabolic syndrome itself. Differences in genetic background, diet,levels of physical activity, population age and sex structure, levels of over- and undernutrition, and body habitus all influence the prevalence of both the metabolic syndrome and its components. Regardless of the underlying genetic and environmental influences that mediate the prevalence of the metabolic syndrome, a higher prevalence will undoubtedly lead to undesirable outcomes such as cardiovascular disease.