Abstract: Objective To explore the relationship between Chlamydia pneumoniae(CP),Mycopla smapneumonia (MP),Helicobacter pylori(HP)and Coxsackie virus(CV)infection and hypertension.Methods On the basis of prevalence survey for hypertension in a Mongolian population,767 hypertensives and 762 normotensives were selected as subjects to conduct a case-control study.The body indexes of the subjects were measured,and blood lipid,blood glucose,IgG antibodies of CP,MP,HP,and CV were examined for all subjects.Results The positive rates of IgG antibodies of CP(40.6%), MP(18.3%),HP(56.3%),and CV(41.4%)in the cases were higher than the positive rates of IgG antibodies of CP (36.8%),MP(18.0%),HP(53.0%),and CV(40.9%)in the controls.But the differences were not statistically significan (P>0.05).After adjustment for confound ing factors,ORs of hypertension related to CP,MP,HP,and CV infection were not statistically significant(P>0.05).Conclusion CP,MP,HP,and CV infections are not associated with hypertension.