Aim To investigate the relationships between polymorphism of candidate gene and carotid artery arteriosclerosis in essential hypertension (EH) patients, the frequencies of C1166 allele of angiotensin II type 1 receptor (AT 1R) gene was determined in normotensives and hypertensives Methods Blood pressure (Bp), body mass index (BMI), fasting serum glucose (Glu), serum total cholesterol (TC) and triglyceride (TG) were measured in 86 normotensives and 120 hypertensives. Intimal-medial thickness (IMT), diameter (D) and I/D of common carotid artery in 32 normotensives and 68 hypertensives were determined. Genomic DNA was extracted from peripheral blood leukocytes by standard method. Polymerase chain reaction (PCR) combined with restriction enzyme digestion was used to detect the polymorphism. Results The frequency of AC genotype and C1166 allele of AT 1R gene of EH patients were higher than that of control (P<0.01 andP<0.05), EH subjects with AC genotype had increased common carotid artery IMT and I/D than those with AA genotype (P<0.05 andP<0.01). Conclusions A1166C polymorphism of AT 1R gene were associated with EH in Chinese population. C1166 allele of AT 1R gene may play a role in arteriosclerosis of hypertension.