Associated with gastritis, peptic-ulcer disease, and gastric carcinoma,Helicobacter pylori(H.pylori) also has been associated with decreased cognitive function and dementia. In this study, we used data from the UK Biobank to further examine associations betweenH.pyloriseropositivity and serointensity and performance on several cognitive tasks in adults 40 to 70 years of age (M = 55.3, SD = 8.1). In these analyses,H.pyloriseropositivity (i.e., either positive or negative forH.pylori) and serointensity (concentration of antibodies againstH.pyloriantigens) in adjusted models were associated with worse function on tasks of Numeric memory, Reasoning, and errors on the Pairs matching test but better function on the Tower rearrangement task. Together, these findings suggest thatH.pyloriseropositivity and serointensity might be associated with worse cognitive function in this age group.