OBJECTIVE: It is much debated whether the metabolic syndrome contributes additional information over and above that provided by the individual components of the syndrome alone. Among HIV-infected individuals, we investigated whether any particular combinations of the components included in the definition of the metabolic syndrome are associated with a higher risk of cardiovascular disease (CVD). RESEARCH DESIGN AND METHODS: We followed 33,347 HIV-infected individuals in a prospective observational study. The effect of combinations of components of the metabolic syndrome (low HDL cholesterol, high triglycerides, high BMI, hypertension, and diabetes) on the risk of CVD was assessed by Poisson regression incorporating interactions between each component pair and adjusting for age, sex, family history of CVD, smoking status, calendar year, and exposure to antiretroviral therapy. We reduced the risk of type 1 errors by randomly splitting the data set for training (70% of sample) and validation (remaining 30%). RESULTS: In the training data set, 671 patients experienced a CVD event over 110,652 person-years. Unadjusted, the presence of metabolic syndrome at study enrollment (>or=3 of the factors) was associated with a 2.89 higher risk of CVD (95% CI 2.34-3.59; P = 0.0001) compared with individuals without the metabolic syndrome. After adjustment for the individual components, the metabolic syndrome as an entity no longer predicted the risk of CVD (adjusted relative risk 0.85; 95% CI 0.61-1.17; P = 0.32). No significant positive interactions were found among the components of the metabolic syndrome. CONCLUSIONS: The presence of the metabolic syndrome in HIV-infected individuals did not appear to increase the CVD risk over and above that conferred by the components of the syndrome separately.