Sepsis is one of the leading causes of mortality in children under 5 years of age. In young febrile children, differentiation between bacterial and non-bacterial causes of fever is necessary owing to a high incidence of viral infections. Early diagnosis of bacteremia in a febrile child is important in reducing childhood mortality. This is a prospective observational study done on 180 children meeting the inclusion and exclusion criteria, who were admitted to the pediatric ward and PICU. History, examination, and provisional diagnosis were made and then the Yale observation scale was applied to children under the study. ROC curves showed that the sensitivity and specificity of YOS at the cut-off value of 12 was found to be 60% and 72% respectively. A YOS score of ≤12 predicts non-serious illness, however a YOS score of >12 does not necessarily indicate serious bacterial infection, and thus should undergo evaluation to confirm bacterial infection.