Sasang constitutional medicine is a major branch of Korean traditional Oriental medicine. The differences of disease susceptibility to be shown in Sasang constitution may be due to genetic factors. Therefore, the authors examined relationship between candidate genes of cerebral infarction (CI) and Sasang constitution. The homozygous deletion allele of the angiotensin converting enzyme gene (ACE/DD), homozygous threonine allele of the angiotensinogen gene (AGN/TT), and the e4 allele of the apolipoprotein E gene (ApoE/e4) are reported to be associated with ischemic heart disease. CI is another atherosclerotic disease; and the effects of these polymorphisms on CI have been confusing. This study investigated whether ACE/DD, AGN/TT, and ApoE/e4 genotypes are associated with CI and whether genetic risk is enhanced by Sasang constitutional classification. The authors ascertained these genotypes in patients with CI (N=211), diagnosed by brain computed tomography. Control subjects for the infarction group were randomly selected from 319 subjects matched for age, sex, and history of hypertension with patients. The ACE/DD genotype was not associated with CI. However, there was significant association between ApoE polymorphism and CI (chi2=15.089, p<.05). Furthermore, frequency of AGN/TT genotype was higher in the patients with CI than in the controls (chi2=20.072, p<.05). The frequency of T allele was 0.91 in patients and 0.82 in controls (chi2=17.237, p<.05). However, Sasang constitutional classification did not increase the relative risk for CI in the subjects with ApoE/e4 or AGN/T allele. These results suggest that ApoE and AGN polymorphism predict CI, but Sasang constitutional classification does not enhance the risk for CI associated with ApoE/e4 or AGN/TT in a Korean population.