Patients with diabetes mellitus (DM) are at risk for Helicobacter pylori infection. This infection has been linked to atherosclerosis and its vascular complications. The aim of this study was to evaluate the: (1) prevalence of H pylori infection in patients with DM; (2) association between diabetic vascular complications and H pylori infection; and (3) influence of H pylori infection on atherosclerosis and inflammatory biomarkers. In this study, we evaluated 80 patients with DM for atherosclerosis; cardiac, cerebral, and peripheral vascular diseases; retinopathy; neuropathy; and nephropathy. We estimated the blood levels of glucose, glycosylated hemoglobin, complete blood cell count, erythrocytic sedimentation rate, lipid profile, tumor necrosis factor-alpha, interleukin (IL)-6, and anti-H pylori IgG antibodies. H pylori infection was detected in 85% of patients versus 76.7% for control subjects. Carotid artery intima-media thickness was significant in H pylori-infected patients. IL-6 and tumor necrosis factor-alpha were significantly associated with H pylori infection. In multivariate analysis, blood glucose, triglycerides, erythrocytic sedimentation rate, IL-6, and tumor necrosis factor-alpha increased the odds for atherothrombotic cause of cerebral ischemia in H pylori infection. We concluded that H pylori infection is common in DM and seems to be linked to the presence of atherosclerosis and ischemic cerebrovascular stroke. This effect could be mediated by increasing cytokine levels.