Most previous studies of associations between insulin sensitivity and common carotid artery (CCA) atherosclerosis have been conducted in small samples, have not used direct measurement of insulin sensitivity, and have yielded inconclusive results. We investigated associations of CCA intima-media thickness (IMT) and diameter (CCA-D) measured by B-mode ultrasound and insulin sensitivity measured by the euglycemic hyperinsulinemic clamp test together with risk factors of the insulin resistance syndrome in a community-based sample of 493 elderly men. The clamp glucose disposal rate was an independent predictor of CCA-IMT in multivariate models adjusting for blood pressure, smoking, serum cholesterol, and body mass index (1% decrease in CCA-IMT for a 1 unit increase in glucose disposal rate, P=0.009). Glucose disposal rate was significantly related to CCA-D in univariate (r=-0.11, P=0.02) but not in multivariate models. In conclusion, this study is the first to establish impaired insulin sensitivity, measured by the euglycemic hyperinsulinemic clamp test, as an independent predictor of CCA-IMT in a population-based sample of elderly men.