This study was intended to estimate the magnitude and explore the determinants of childhood drowning in rural Bangladesh. A cross-sectional survey as well as a population-based case - control study was conducted. By multistage cluster sampling 51 147 children aged 1 - 4 years were identified from 108 827 rural households. All drownings in children aged 1 - 4 years in the preceding 5 years were identified and recruited as cases and two living children of the same age group were selected from the same localities as controls. Socio-economic, demographic, environmental and other related information was collected from mothers of both cases and controls by face-to-face interview with the help of structured questionnaires. The incidence of drowning among children aged 1 - 4 years old was 156.4 per 100 000 children-year. The highest rate (328.1 per 100 000; 95% CI 254.8 - 421.7) was observed in 1 year old male children. The proportional mortality due to drowning in the children was 27.9%. Mothers' age and literacy and family income were identified as risk factors. Drowning is one of the major causes of 1 - 4 years childhood mortality in Bangladesh. One-year-old male children from poor families were at great risk of drowning in rural Bangladesh.