Anti-Helicobacter pylori antibodies were determined in 157 institutionalised Cantonese children, mean age 9.5 +/- 3.9 (SD) years, with profound neurodevelopmental disabilities. Eighty-seven (55.4%) were H. pylori seropositive compared with four of 50 (8%, P > 0.0002) of an age-matched control group, mean age 7.2 +/- 4.3 (SD) years. Eight of 15 seropositive children with a recent history of upper gastrointestinal bleeding underwent endoscopy and in all cases gastric infection with H.pylori was confirmed. Anthropometric data from institutionalised children revealed marked malnutrition but showed no significant difference between seropositive and seronegative children. Disabled children receiving long-term residential care in Hong Kong are confirmed to be at increased risk of H.pylori infection.