Introduction: Nursing protocols in management of dehydration in children has improved the quality and consistency of care for the children with dehydration. Aim of the Study: The present study aimed to investigate the effect of nursing protocol in management of dehydration in children. Study Design: A quasi- experimental design was utilized. Setting: The study was carried out at Pediatric Emergency and Medical Departments/Pediatric Children's Hospital, affiliated to Ain Shams University Hospitals. Subjects: The study included 30 nurses caring for children suffering from dehydration. Also, the study sample involved 30 children diagnosed with dehydration and their parents in the previously mentioned settings. Tools of the Study: The involved children and their parents' assessment sheet, nurses' questionnaire sheet for knowledge assessment pre- and post-implementation of nursing protocol, observational checklists and nursing protocol in management of dehydration in children. Results: It was clear that the majority of the studied nurses had satisfactory knowledge and competent practices regarding management of dehydration in children-post implementation of nursing protocol. There was a statistically significant difference between total nurses' knowledge and practice. Conclusion: Implementation of nursing protocol had a positive effect on the improvement of nurses' knowledge and practice regarding care of children suffering from dehydration. Recommendations: Raising awareness of nurses regarding nursing protocol in management of dehydration in children.