Ventilator-associated pneumonia (VAP) is defined as nosocomial pneumonia developing 48 hour or more after initiation of mechanical ventilation. It is the second most common nosocomial infection in pediatric intensive care units (PICUs), accounting for 20% of all nosocomial infections in the pediatric population. The prevention of VAP is a major focus of many recent safety initiatives and focuses on modification of risk factors. The main aim of the study was to evaluate the effect of implementing training program for nurses onprevention of pediatric ventilator associated pneumonia. A quasi-experimental research design was used in the study. The study was carried on Medical Intensive Care Unit at Mansoura University Children's Hospital. The study involved a convenient sample of 40 critical care nurses regardless of their age, education and years of experience. The study was conducted in Pediatric Intensive Care Unit at Mansoura University Children hospital. Two tools were used for data collection including questionnaire to assess the nurses' knowledge about Pediatric ventilator-associated pneumonia and its prevention and pediatric ventilator-associated pneumonia prevention observation checklist. The results of the present study indicated that, the nurses' knowledge and practices of ventilator-associated pneumonia and its prevention in PICU was improved after the implementation of the training program either immediately or 3 months later than before its implementation. There is also a need for periodic refreshing in-service training program should be provided to nurses' in PICU in order to improve their knowledge and practices regarding VAP prevention.