OBJECTIVES: To estimate the utility scores for diarrheal children aged under 5 years and their caregivers and to identify the influencing factors which affected on these. METHODS: Hospitalized diarrheal children aged between 2 months and 5 years and their caregivers at were recruited in this cross-sectional study at three hospitals in Phetchabun province. The EQ-5D instrument was used to collect the quality of life (QoL) data at the first date of admissionQuality of life of diarrheal children was measured as proxy report from caregiver while QoL of caregiver was measured as self-report. The raw data was converted to utility values using the Thai algorithm. The clinical severity of diarrheal children was rated using the Vesikari clinical severity scoring systemStepwise multivariate linear regression was applied to explore the impact of the various factors on the utility value of children and caregivers RESULTS: Mainly domains of diarrheal children were affected as pain/discomfort and anxiety/depression similarly to their caregivers. On multivariate regression analysis, factors which affected the children’s utility significantly were Vesikari score, child’s age and child’s gender. Next, reduced QoL of their caregivers related to caregiver’s gender and Vesikari score.  CONCLUSIONS: Diarrhea had an impact on quality of life of children and their caregivers. It appeared that QoL of children with diarrhea was impacted worse in girls, those with high severity score and was associated with age. In addition, the diarrheal severity and female gender reduced the impact of diarrhea on QoL of caregivers. These results can be useful to evaluate the cost-effectiveness of vaccines against diarrhea such as rotavirus vaccines.