Patients with rheumatoid arthritis (RA) have accelerated atherosclerosis. The metabolic syndrome, a cluster of cardiovascular risk factors, identifies cardiovascular risk. We tested the hypotheses that patients with RA have a higher prevalence of the metabolic syndrome, particularly the WHO-defined syndrome that requires insulin resistance, and that this is associated with coronary atherosclerosis. The prevalence of the metabolic syndrome was determined using the modified WHO and NCEP III criteria in 154 patients with RA (88 with early RA and 66 with long-standing RA) and 85 control subjects. Coronary-artery atherosclerosis was detected by electron beam computed tomography. The WHO-defined metabolic syndrome was present in 42% of patients with long-standing RA, 31% with early RA and 11% of controls (P<0.001); the NCEP-defined metabolic syndrome was present in 42% of patients with long-standing RA, 30% with early RA and 22% of controls (P=0.03). Patients with the WHO-defined metabolic syndrome had an increased risk of having higher coronary-artery calcification scores, independent of age and sex (OR=2.02, 95% CI: 1.03-3.97, P=0.04). In conclusion, patients with RA have a higher prevalence of the metabolic syndrome than control subjects. Inflammation-associated metabolic syndrome is a mechanism that may contribute to increased coronary-artery atherosclerosis in RA.