Abstract: Objective To investigate the relationship between genetic polymorphism of angiotension-converting enzyme(ACE) gene and ischemic stroke.Methods Polymerase chain reaction(PCR)and DNA sequencing were used to detect ACE genotypes in 166 patients with ischemic stroke and 120 healthy controls in a Han population.Results Among the cases with ischemic stroke,the I/D frenquencies of D/D,I/D,I/I were 71.1%,24.7%,4.2%,and that of the controls were 50.8%,41.7%,7.5%,respectively.There were significant differences between the two groups.The relative risk of suffering from ischemic stroke in D/D gene carriers was 2.38 and 2.79 times compared to I/D and I/I gene carriers(95% confidence interval95%CI of I/I=1.463-3.872 and 95%CI of I/D=1.914-4.167),and the differences were statistically significant(P<0.05).Conclusion ACE polymorphism is associated with ischemic stroke.The ACE gene D/D allele carriers have a significantly higher risk of ischemic stroke than other genotype carriers and D/D allele may be a genetic susceptibility gene for ischemic stroke.