Background: Insulin resistance (IR) is associated with a significant increase in the risk of coronary artery disease. The serum apolipoprotein B-100 and Apo B/Apo A1 ratio are important markers of IR in non-diabetic, normoglycemic subjects. Quantity of coronary artery calcium is a noninvasive surrogate of coronary atherosclerotic burden that is strongly correlated with angiographic coronary artery disease and is predictive of future coronary heart disease events. The aim of the present study was to investigate the association between IR and coronary atherosclerosis. Methods: A total of 165 patients (mean age = 60.1짹11.9 years, 110 males) who have no history of diabetes were examined. Coronary atherosclerosis was assessed by measuring coronary calcification using multidetector row computed tomography (MDCT) and expressed as a total calcium score. The total calcium score was log-transformed because of its skewed distribution. The association between apolipoproteins and coronary calcification was evaluated after adjustment for age and sex. Results: The Apo B, Apo B/Apo A1 ratio showed positive correlations with log total coronary calcium score (r=0.354, 0.321, p<0.001, <0.001, respectively). Linear regression analyses showed that increased Apo B/Apo A1, Apo B were associated with a higher log total coronary calcium score (beta-regression coefficient 0.354, 0.321, 95% confidence interval 0.13-0.42, 0.04-0.14, respectively). Conclusion: Total coronary calcium score was strongly and independently associated with IR.