In 102 patients with systemic lupus erythematosus (SLE) and 101 controls, the prevalence of metabolic syndrome was compared using ATP III and World Health Organization (WHO) criteria, and associations with cardiovascular risk and lupus characteristics were studied. SLE patients had a significantly higher prevalence of metabolic syndrome than controls when using WHO criteria (32.4% vs 10.9%, p<0.001), while the difference was not significant when using ATP III criteria (29.4% vs 19.8%, p = 0.14). Among SLE patients, both definitions were associated with higher CRP concentrations; the ATP III definition was also associated with significantly higher homocysteine, Lp(a), and cholesterol levels. The metabolic syndrome may, therefore, provide a link between inflammation and increased cardiovascular risk in SLE patients.