Background: Clinical nursing competence is the capacity to apply care by integrating information, skills, attitude, beliefs, and experience. It reflects the nursing professional's feelings, ideas, and judgement. Aim: the study aimed to evaluate the effect of Competency Based Training Program on Nurses' Performance Regarding Endotracheal Tube Suction for Neonates on Mechanical Ventilator. Method: A quasi-experimental design was used to conduct the study at Neonatal Intensive Care Units (NICUs) and Surgical Neonatal Intensive Care Unit "SNICU" of Benha Specialized Pediatric Hospital. The study included 70 nurses who working in the previously mentioned setting. Tools: Researchers used five tools as; a structured interviewing questionnaire, an observational checklist, nurses' attitude questionnaire, Nurse Competence Scale, and nurses' opinion questionnaire. Results: Less than three quarters of studied nurses had good knowledge and the most of them had competent practice post competency-based training program. Also, the majority of nurses had positive attitude post competency-based training program and there was highly statistically significant difference in nurses' competence score pre and post competency-based training program. Conclusion: The implementation of the competency-based training program improved nurses' performance regarding endotracheal tube suction for neonates on mechanically ventilated. Recommendation: Develop periodic educational and training courses for nurses working at the neonatal intensive care units regarding care of endotracheal tube suction for neonates on mechanical ventilator. Further research should be done with large sample is recommended to ensure generalization of the results.