The adult treatment panel III (ATP III) of the National Cholesterol Education Program recognizes metabolic syndrome (MS) as a secondary target for risk-reduction therapy given the well-known increase in risk of cardiovascular disease (CVD) by all MS components. We investigated potential CVD risk arising from 17 laboratory variables in postinfarction patients with MS by identifying such patients from the Thrombogenic Factors and Recurrent Coronary Events (THROMBO) study using slightly modified ATP III criteria for MS. This gave 272 patients with MS out of a total of 766 postinfarction patients without history of diabetes. Comparison between non-MS and MS patients using Kaplan-Meier analysis revealed no difference in outcome between groups. Additionally, a proportional hazards model applied to dichotomized laboratory parameters demonstrated only apoB as a significant predictor of risk for recurrent coronary events in MS patients with hazard ratio, 1.97 (95% CI; 1.08, 3.60; P < 0.05). We conclude that there is no difference in outcomes between non-MS and MS postinfarction patients; that apoB is significantly associated with risk for recurrent coronary events in postinfarction patients with MS; that further studies would be needed to recommend the routine determination of apoB in these patient groups.