The author investigated whether ACE/DD, AGN/TT, and ApoE/ε4 genotypes are associated with CI and whether genetic risk is enhanced by Sasang constitutional classification. The author 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, gender, 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 (x²=15.089, p<.05). Furthermore, frequency of AGN/TT genotype was higher in the patients with CI than in the controls (x²=20.072, p<.05). The frequency of T allele Was 0.91 in patients and 0.82 in controls (x²=17.237, p<.05). However, the Sasang constitutional classification did not increase the relative risk for CI in the subjects with ApoE/ε4 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/ε4 or AGN/TT in a Korean population.