Diarrhoeal disease is still one of the major causes of mortality and morbidity of children in developing countries. Our objective was to assess the prevalence of diarrhoeal disease among male schoolchildren in Jeddah and to identify the associated risk factors, especially those related to drinking water and sanitation disposal. This cross-sectional study was conducted randomly where self-administered questionnaires were issued to parents through the schools. The data were collected from 1,064 respondents indicating that 14.9% of the children had diarrhoea during the previous month. The main risk factors were: the number of children under five years living in the same house (OR per child 1.34, 95% confidence intervals 1.15–1.56), being of Saudi nationality (OR 1.75, 1.08–2.84), reporting sewage spillage near the home (OR 1.69, 1.14–2.53), eating out after school hours (OR 1.74, 1.16–2.60), not drying hands after washing them (OR 1.66, 1.10–2.51), using reusable cloths or sponges to dry dishes (OR 1.70, 1.14–2.52).