To evaluate the possible role of diet in the transmission of Helicobacter pylori, we compared H pylori seroprevalence among Seventh-Day Adventists (who are vegetarian and abstain from alcohol, caffeine, and meat; n = 94) and two non-Seventh-Day Adventist control groups (n = 168). With the use of an enzyme-linked immunosorbent assay H pylori antigen prepared in a French pressure cell, we found no difference in seroprevalence among these groups; however, seropositivity strongly correlated with age and black race.