Aim To investigate the relations between Helicobacter pylori(Hp) infection and acute myocardial infarction. Methods The concentration of Hp specific IgG antibody and the optical density (OD) of Hp specific IgM antibody were measured in 51 patients with acute myocardial infarction (AMI group), 42 patients with old myocardial infarction (OMI group) and 31 normal controls (NC group) who had angiographically confirmed no coronary artery disease. Simultaneously, the changes and relationships between C-reative protein (CRP), fibrinogen (Fg) and Hp infection were determined in the three groups. Results 39 of the AMI group (76.47%) were seropositive for Hp average concentration (OD) of IgG (IgM) antibody to Hp was significantly higher in the AMI group than that of the NC group (p<0.05), but they were not significantly higher than that of the OMI group (p<0.05). The relation between the Hp infection and acute myocardial infarction (AMI) was strong (odd ratio is 3.047, 95%CI is from 1.055 to 8.796, χ 2=24.241, P=0.03). Adjustment for the major cardiovascular risk factors didn't attenuate this relation (odds ratio is 3.262, 95%CI is from 1.015 to 10.485, χ 2=23.94, P=0.047). The average concentration of IgG antibody to Hp, the levels of Fg and CRP were significantly higher in the AMI group compared with those in the NC group. Those who were Hp positive in the AMI group had not only significantly hiher levels of CRP and Fg than those who were Hp negative in the same group (p<0.05) but also than those who were Hp positive in the OMI group (p<0.001). There was still a positive relation with the average contentration of IgG to Hp in Hp positive patients of the AMI group (p<0.05). Conclusion There is a significant relation between Hp infection and acute myocardial infarction. There is a certain relation between Fg, CRP and Hp infection, too.