Abstract: Present studies examined the DNA polymorphisms in the AGT genes in a Chinese population in Henan province of central China. By using PCR-RFLP and maximum likelihood estimation (MLE), we estimated the pattern of intragenic linkage disequilibrium and the haplotype structure and explored the possible association between the polymorphisms of AGT gene and essential hypertension in a case-control study. Seven polymorphic sites (SNPs) and seven major haplotypes of AGT gene were analyzed. Among the individual SNP pairs examined, the A-6G, C+31T and M235T are nearly completely disequilibrium. All those single polymorphism loci were individually not associated with hypertension. But we found the frequency of haplotype H2 (-217: G, -152: G, -20: A, -6: G, +31: T, 174: T, 235: M) was significantly higher in controls than patients (P=0.010). Our study suggested that few haplotypes derived seven polymorphism loci could account for the most of the variation in AGT gene in Chinese Hans. The haplotype H2 of AGT gene might represent or be in disequilibrium with a genetic protective factor against EH.