Background: The role of the pediatric nurse in managing a chest tube in a pediatric child is vital for ensuring the child's safety, comfort, and optimal recovery. Aim: To evaluate the effect of chest tube instructional package application on pediatric nurses' performance. Design: One group pre-posttest quasi-experimental research design utilized to achieve the aim of the current study. Setting: The study was conducted in post-operative cardiac care and emergency units of Cairo University Specialized Pediatric Hospital (CUSPH). Sample: A convenient sample of 50 nurses who cared for children with chest tubes in the post-operative cardiac care unit and in the emergency unit. Tools: four tools were used to collect the required data a nurses' personal data tool, nurses' knowledge assessment tool, an observational checklist and the child's hospital stay tool. Results: the study revealed that there were statistically significant differences between total mean score of nurses' knowledge before and after application of the instructional package as well as nurses' practices mean score P value = 0.000. Conclusion: The study concluded that the instructional package has a significant impact on nurses' performance in caring for children with chest tubes. Recommendations: All nurses should be mandated by the Egyptian Ministry of Health to be certified by current instructional package about chest tube care. The credential should only be valid for one year, especially for nurses working in intensive care units.