The metabolic syndrome is a cluster of risk factors associated with an increased risk for cardiovascular disease and type 2 diabetes. Based on data from 1988 to 1994, it is estimated that 24% of adults in the United States meet the criteria for diagnosis of the metabolic syndrome. The use of certain medications may increase the risk of the metabolic syndrome by either promoting weight gain or altering lipid or glucose metabolism. Health providers should recognize and understand the risk associated with certain medications and appropriately monitor for changes related to the metabolic syndrome. Careful attention to drug choices should be paid in patients who are overweight or have other risk factors for diabetes or cardiovascular disease.