AimThis study investigated the microbial quality of food and water consumed by children in four slums in Dhaka, the capital of Bangladesh, together with the associated risk factors.MethodsThis crossâsectional study took place from December 2015 to May 2016 and focused on 360 children under the age of five. We recorded household food security, namely adequate food for a healthy life, socioâeconomic and nutritional status, hygiene and feeding practices. Food and water samples were analysed.ResultsWe found that 63% of the children were malnourished and 58% were stunted. Yeast and moulds were detected in 86% of the food samples and coliforms in 73%. All the water samples were contaminated with faecal coliforms, yeasts and moulds and Staphylococcus. Food insecurity affected 83% of households. Children were twice as likely to be malnourished if they were born with a perceived low birthweight or their mothers did not wash their hands with soap after cleaning the child's bottom following defecation. Exclusively breastfed children were less likely to develop malnutrition.ConclusionChildren from the Dhaka slums were frequently stunted and malnourished and contaminated food and water was common. Integrated efforts are essential to create public awareness about hygiene.