The authors tested in 134 African American and European American children whether hostility measured at study entry predicted the metabolic syndrome risk factors an average of 3 years later. Hostility was measured with the Cook-Medley Hostility Scale (W. W. Cook & D. M. Medley, 1954) and with ratings of Potential for Hostility from interview responses. Metabolic syndrome was based on having at least 2 of the following risk factors above the 75th percentile of scores for their age, race, and gender group: body mass index, insulin resistance index, ratio of triglycerides to high-density lipoprotein cholesterol, and mean arterial blood pressure. Children who exhibited high hostility scores at baseline were likely to exhibit the metabolic syndrome at the follow-up. The results highlight the potential importance of early prevention and intervention of behavioral risk factors for cardiovascular disease.