Globally, different episodes of diarrhoeal diseases are one of the leading causes of childhood morbidity and mortality, especially in developing countries. Diarrhoeal diseases among children under five years of age have been considered as the major causes of morbidity and mortality in Bangladesh although it has declined recently. In this study, the most recently published Multiple Indicator Cluster Survey 2019 (MICS 2019) data were used to observe the prevalence of childhood diarrhoea and to identify the socio-economic and demographic risk factors of childhood diarrhoea in Bangladesh. The chi-square test was used in this study to identify the risk factors of childhood diarrhoeal diseases in Bangladesh. The overall prevalence of diarrhoea among children under five years of age in Bangladesh was found 6.9% in the last two weeks preceding the survey. The findings of the study identified that child age less than two years, an unimproved facility of toilet or source of drinking water, floor material made of earth/sand, no handwashing place observed in dwelling/ yard/plot, lower or no education of mothers and household heads, lower economic status, three or more under-five children living in the family are the most potential risk factors of childhood diarrhea in Bangladesh. Improved source of drinking water supply, better sanitation, hygiene practice, mother’s knowledge and consciousness about diarrhoea and, timely treatment and can reduce the burden of childhood diarrhoea in Bangladesh. The quality of existing child healthcare services like oral rehydration therapy (ORT) during diarrhoea, rotavirus vaccination programs should be improved at all stages without any discrimination which will contribute to a reduction in childhood morbidity and mortality due to diarrhoea in Bangladesh.