1. Objectives The purpose of this study was to prove the correlation between risk factor of cardiovascular disease and Sasang Constitution and to investigate the effect of oxygen free radical on this correlation. 2. Methods We analyzed 129 patients who visited Cheonan oriental medical hospital from Apr 1, 2007 until May 31, 2007, for medical examination, which Includes Sasang Constitution examination, blood chemistry test and physical examination. And we classified their results into 4 groups based on with blood lipoprotein level and body mass index. 3. Results and Conclusions Mean of lipoprotein in blood was not significantly different among constitutions but with body mass index, was significantly higher in Taeumin than others. And count of dyslipoproteinemia was significantly higher in Taeumin group than soeumin. Therefore, according to our results, risk of cardiovascular disease was higher in Taeumin than other constitutions. Oxygen free radical did not have much effect on correlation between risk factor of cardiovascular disease and Sasang Constitution. However, there was some evidence in soeumin group, that oxygen free radical may have effect on origination of hyperlipidemia.