Abstractobjectives To determine and compare socio-demographic, nutritional and clinical characteristics of children under five with diarrhoea living in slums with those of children who do not live in slums of Dhaka, Bangladesh.methods From 1993 to 2012, a total of 28 948 under fives children with diarrhoea attended the Dhaka Hospital of icddr,b. Data were extracted from the hospital-based Diarrhoea Disease Surveillance System, which comprised 17 548 under fives children from slum and non-slum areas of the city. conclusions Slum-dwelling children are more malnourished, have lower immunisation rates (measles vaccination and vitamin A supplementation) and higher rates of measles, are more susceptible to diarrhoeal illness due to V. cholerae and suffer from severe dehydration more often than children from non-slum areas. Improved health and nutrition strategies should give priority to children living in urban slums.