Background and Objectives: Cardiovascular disease is the most common cause of death in developed countries. In addition to traditional risk factors for cardiovascular disease, nowadays, accumulating evidence indicates that a variety of infections contribute to pathogenesis of atherosclerosis, (We investigated whether Helicobacter pylori infection is related to Prevalence of coronary heart disease) there is controversy concerning the impact of H. pylori infections in atherosclerosis. Materials and Methods: This case-control study was carried out on 130 subjects who underwent coronary angiography in the School of Medicine, Tehran University of Medical Sciences, Iran, from Oct 2006 to Oct 2007. According to angiography findings, the patients were grouped into cases (n=70) with Coronary Artery Disease (CAD), and normal control group (n=60). Then, using ELISA method, specific anti H. pylori IgGs were measured in all subjects. The connection between CAD and H. pylori infection was studied. Results: Among the 130 patients, anti-H. pylori IgGs were detected in 80% of cases and 65% of control subjects (p=0.05). The investigation shows that CAD correlated significantly with hypertension, diabetes, and smoking (p<0.05) although there was no associations between these traditional risk factors, and H. pylori infection. Conclusion: These findings raise the possibility that exposure to H. pylori may lead to an increased risk of coronary artery disease independent of other risk factors.