Background: A population-based study was conducted in Taiwan to investigate the prevalence of insulin resistance and high serum insulin concentrations and their relationships with potential atherosclerotic risk factors. Methods: We studied 2165 subjects, ages 35, from a community cohort. Results: The distributions of fasting insulin were skewed to the right, with higher concentrations in women than in men. As age increased, insulin increased in women, but decreased in men. As fasting insulin concentrations increased, postloading insulin, glucose, blood pressure, body mass index, waist-to-hip ratio, total cholesterol, triglycerides, LDL-cholesterol, apoprotein B, plasminogen activator inhibitor 1, tissue plasminogen activator, and fibrinogen increased, but lipoprotein(a), HDL-cholesterol, and apoprotein A1 decreased. Multiple logistic regression showed that obesity, high LDL-cholesterol, and low HDL-cholesterol were significant predictors of hyperinsulinemic status. Conclusion: The study subjects with insulin resistance syndrome and related risk factors may be at risk for atherosclerosis, thrombosis, and other coronary heart diseases.