Gastro-intestinal diseases continue to be a major health problem in primary schools in the UK. This study, which took place in 20 primary schools in the Leeds area, investigated the presence of faecal indicator bacteria on children's hands and environmental surfaces. Faecal streptococci were used as an indicator of faecal contamination. A handwashing knowledge score was developed for each child. Those children with good hygiene knowledge had less faecal contamination on their hands (relative risk: 1.4, 95% CI = 1.09-1.81, P = 0.005). Those schools with higher hand counts were more likely to have had a reported outbreak of gastroenteritis in the past. Values of the Townsend Deprivation Index, an indicator of deprivation, were compared with the hand results and those schools in high deprivation areas had higher hand counts. Of the swabs taken from surfaces in the toilet areas and classrooms, the carpets in the classrooms were the most frequently contaminated surfaces.