In the past 10 years, there has been interest in a “metabolic syndrome” that might be associated with cardiovascular disease or diabetes. The first sets of criteria differed markedly, and their accuracy was equivocal. More recent definitions may be an improvement over previous ones. The metabolic syndrome may be most useful as a predictor of cardiovascular disease in nondiabetic subjects. It encourages healthcare providers who are confronted with a single risk factor to look for others. When multiple risk factors are found, it promotes consideration of behavioral interventions, such as weight loss and increased physical activity, instead of a pharmacological treatment for each risk factor. Such behavioral interventions were more effective than metformin in reducing the incidence of diabetes and of other components of the metabolic syndrome in one randomized, controlled study.