Objectives: a) To identify cases of diarrhoea among children at paediatrics OPD, and b) to explore knowledge about use of oral rehydration salt (ORS) among mothers of children suffering from diarrhoea. Methods: It was an exploratory study conducted at a tertiary care hospital with cases presenting diarrhoea in paediatrics OPD. A close ended questionnaire was administered to mothers to access their knowledge about ORS. Results: Out of 3,087 patients who attended paediatrics out-patient department (OPD) during the study period, 179 (5.8%) were infants/children suffering from various types of diarrhoea. Cases belonging to rural areas were 53%. The ratio of infants was higher, with high incidence in children on mixed feeding. Majority of cases suffered from acute watery diarrhoea. Severe dehydration was in 3% of cases, moderate dehydration in 41%, and no dehydration in 56%. All mothers, except two, were aware of ORS use, and 94% of them mentioned ORS as beneficial in diarrhoea, although 85% used ORS on their own which shows a gap between knowledge and practice. Ratio of mothers with adequate knowledge of preparing ORS was higher in mothers from urban areas. Conclusion: Majority of mothers with children having diarrhoea were from rural areas and uneducated. More than half of cases were on mixed feeding. Although all but two mothers was aware of the use of ORS and more than three quarters knew how to prepare it, but a less number used ORS on their own when needed. Not all medical practitioners prescribed ORS.