Background: It is not known whether infection by a specific pathogens is associated with type 2. We examined the association between chronic infection with four pathogens (Chlaydia pneumonia, Helicopacter pylori, Herpes simplex virus type 1 and cytomegalovirus) and type 2 diabetes mellitus in a general Iranian population, in the northern Persian Gulf. Materials and Methods : In a population-based study of men and women aged >25 years, a random sample of 1754 (49.2 % males, 50.8 % females) subjects were evaluated. Sera were analyzed for immunoglobulin G antibodies to C. pneumoniae, HSV-1, H. pylori, and CMV using enzyme-linked immunosorbent assay. Type 2 diabetes mellitus was defined according to criteria of American Diabetes association. Results: A total of 150 (8.6%) subjects had type 2 diabetes mellitus. In the diabetic group, 42% were seropositive for C. pneumoniae, 64.7% for H. pylori, 92.9% for HSV-1 and 94.7% for CMV. In multiple logistic regression analyses, seropositivity for C.pneumoniae (OR=0.89, CI: 0.60-1.34, P=0.602), H. pylori(OR= 0.95, CI: 0.64-1.41, P= 0.808), HSV-1(OR= 1.76, CI: 0.86-3.62, P=0.120) ,CMV(OR=0.99, CI: 0.43-2.27, P=0.982) did not show a significant independent association with type 2 diabetes mellitus after adjustment for age, sex, chronic low-grade inflammation, and cardiovascular risk factors. Conclusion: There was not a strong association between type 2 dibetes mellitus and prior infection with viral and bacterial pathogens that had been previously correlated with coronary artery disease as well as carotid atherosclerosis.