Abstract: Objective To investigate the relationship between angiotension conve rting enzyme(ACE)gene insertion/deletion(I/D)polymorphism,angiotension Ⅱ type 1 receptor(AT₁R)gene A1166C polymorphism and essential hyperten sion in Kazakh.Methods Acase-control study was conducted in 220 cases and 220 controls.Polymerase chain reaction and restrict fragment length polymorphism(PCR-PELP)technique were used to detect the geno type polymorphism.Results Among the cases with hyperten sion,the I/D frenquencies of DD,ID,Ⅱ were 43.64%,34.54%,21.82%,and that of the controls were 27.72%,48.64%,23.64%,respectively.There was a significant difference between the two groups (χ²=19.89,P<0.01).60.91% of D and 39.09% of Iallele were distributed in hype rtention cases,while 47.95% of D and 52.05% of I in controls with a significant difference between the two groups(χ²=14.89,P<0.01).Among the cases with hype rtension,the A1166C frenquencies of AA and AC were 78.6%,21.4%,and that of the controls were 81.6%, 18.4%,respectively,with no significant difference between the two groups(χ²=0.51,P>0.05).89.3% of A and 10.7% of Callele were distributed in hype rtention cases,while 90.7% of A and 9.3% of Cincontrols and there was no significant difference between the two groups(χ²=0.45,P>0.05).Conclusion The DD and AA,AD and AC geno type of the gene mightinc rease the risk of hype rtension.There is no relationship between A1166C genepolymorphism of AT₁R gene and hype rtension in Kazakh people.There is an in teraction between ACE gene and AT₁R gene.