Globally, many children under five years live in households without access to quality drinking water, while many more live in households without access to improved sanitation facilities. Therefore, more than 1.5 million children die from diarrhoea every year and a lot more have their development disrupted and their health undermined by diarhoeal-related diseases. Today diarrhoea is the leading cause of mortality and morbidity, especially among young children in developing countries and in Kenya it contributes to 12.8% of the under five deaths. In Mandera, it is a major factor contributing to other health problems such as malnutrition and mortality. Various organizations have had Water, Sanitation and Health Education interventions in the district, all aimed at containing diarrhoeal diseases especially among the under fives. However, it is not known if these interventions have had any effect on diarrhoeal morbidity among the children. The main objective of this study was to assess the effects of these interventions on diarrhoeal morbidity among children under five years in Mandera district.