BACKGROUND AND OBJECTIVES: The renin-angiotensin system (RAS) genes have been studied extensively as etiologic essential hypertension (EH) candidate genes in human populations worldwide. The angiotensin I-converting enzyme (ACE) plays an important role in the RAS for the regulation of blood pressure. Recent reports on the association of ACE gene polymorphisms with EH and the related cardiovascular diseases have been controversial. Therefore, this study investigated the association of three polymorphisms (I/D, G14480C and A22982G) in the ACE gene with EH in Koreans. SUBJECTS AND METHODS: This study recruited a sample population of 887 Koreans (comprising of 461 controls and 426 EH cases) from Cardiovascular Genome Center in Korea. The ACE gene polymorphisms were determined by a polymerase chain reaction and a SNP-IT assay. RESULTS: The genotype and the allele frequencies of all three polymorphisms in the hypertensives and the normotensives not significantly different (p>0.05). In the female control group, there was a significant difference in SBP among the genotype with the I/D polymorphism (p<0.05). There was also an association between the ACE polymorphisms and the hypertensive male group with the total cholesterol level. Haplotype analysis showed that none of the haplotypes were significantly associated with hypertension. CONCLUSION: ACE polymorphisms do not appear to have any apparent association with essential hypertension in Koreans, who have a more homogeneous genetic structure than other ethnic groups.