Background: IV therapy is a commonly performed nursing procedure that involves the delivery of fluids, and occasionally medications, to a child who is unable to maintain a regular fluid balance through oral consumption. The choice of route, amount, and type of fluids administered are critical factors in effectively managing a child undergoing IV therapy. The study aimed to evaluate the effect of intravenous therapy administration guidelines on pediatric nurses' knowledge, practice, and selected child's outcomes at ICUs. One group pre-posttest quasi-experimental research design was utilized to achieve the aim of the current study. The study was conducted in Cardio-thoracic, Neurological Intensive Care Units (ICUs) and Neonatal Intensive Care Unit (NICU) at Cairo University Specialized Pediatric Hospital (CUSPH). A Convenient sample of 30 nurses who cared for children in ICUs in CUSPH. Four tools were used to collect data a structured interview questionnaire, Nurses' Knowledge Assessment Questionnaire, and Nurses' Practice Checklist and children's outcomes assessment checklist Results: the study revealed that there were statistically significant differences between total mean score of nurses' knowledge before and after receiving the IVT administration guidelines as well as, nurses who received the IVT administration guidelines had higher mean score of practice. Children who are provided with care by nurses who have received guidelines for intravenous therapy administration had better outcomes compared to children who are cared for by them after receiving the IVT administration guidelines. Conclusion: the current study concluded that nurses who receive the IVT administration guidelines had higher mean score of knowledge and higher mean score of practice than before. Better outcomes in children receiving care from nurses after IVT administration guidelines Recommendation: training programs about IVT administration guidelines recommended to improve outcomes of IVT administration.