Three areas had benefited from drainage improvements, three from both drainage and sewerage improvements, and three from neither. Mothers recorded diarrhoea in their children (under 5yrs) daily for one year. The incidence of diarrhoea in children with drainage was less than two-thirds, and in areas with drains and sewers less than one-third, of the incidence in areas with neither drains or sewers. The study provides evidence that community sanitation can have an impact on diarrhoeal diseases even without measures to promote hygiene behaviour. Trans Royal Soc Trop Med Hyg 2003;97:1-6.