The purpose of this study was to determine the seroprevalence of Helicobacter pylori and risk factors for infection in gastrointestinal endoscopy personnel and those caring for developmentally disabled individuals. We administered a structured, one-page questionnaire. Helicobacter pylori status was determined serologically. In all, 107 health-care workers participated. Direct patient contact, exposure to gastrointestinal secretions, history of peptic ulcer, and acid-suppressing medicine use were more frequent among those who worked with the developmentally disabled. Seroprevalence of Helicobacter pylori was 24% in endoscopy personnel and 47% among those who cared for the developmentally disabled (P = 0.02). Bed-sharing with a sibling during childhood, working with the developmentally disabled, and direct patient contact were associated with Helicobacter pylori infection; exposure to patients' gastrointestinal secretions was not. We conclude that those caring for developmentally disabled individuals have a higher risk of occupational acquisition of Helicobacter pylori infection than endoscopy personnel.