Abstract: Objective To explore the relationship between C-reactive protein and hypertension,and the interaction of C-reactive protein and other cardiovascular risk factors on hypertension in Mongolian people.Methods On the basis of a prevalence survey,767 hypertensives and 762 nounotensives aged ≥30 were selected as subjects to conduct the case-control study.All subjects were investigated for cigarette smoking,alcohol intake and the history of cardiovascular diseases Subsects' body measurements,blood glucose,lipids,insulin and C-reactive protein were measured with standardized methods All data were analyzed with SPSS softw are version 13.0.Results The content of C-reactive protein (2.10±0.83 mg/L)in cases was significantly higher than that of(1.80±0.77mg/L)in controls After adjushnent for other factors,subjects was divided into four groups according to the content of C-reactive protein OR values of hypertention for three groups from low to high were 1.144 (0.840-1.559,1.330 (0.970-1.824) and 1.556(1.116-2.172),respectively,compared to the group with the lowest content of C-reactive protein There was a trend of hypertension prevalence increasing with the content of C-reactive protein(χ_MH²=7.397,P=0.007).There was a significant interaction between C-reactive protein and cigarette smoking and insulin resistance on hypertension after adjushnent for other risk factors,and the relative exess risks due to the interaction (RERI) were 0.799 (P<0.01) and 0.651(P<0.05),respectively.Conclusion High content of C-reactive protein was related with hypertension,and there was a trend of hypertension prevalence increasing with the content of C-reactive protein There were interactions between C-reactive protein and cigarette smoking and insulin resistante on hypertension.