Oxygen is life essential so it is important for nurses who are responsible for oxygen administration to be familiar with its indications and potential hazards. Past studies have shown that healthcare professionals may lack awareness and knowledge regarding oxygen therapy, and its implementation often has several obstacles. Aim : To evaluate the effect of designed guidelines about oxygen therapy for neonates on nurse’s knowledge and skills. Design: A quasi experimental one group pre/ post test research design was used. Setting: The current study was conducted in NICUs that allocated on the fourth floor of El Manial University Hospital (Kaser Al Aini) , Sample: sixty seven bedside nurses were recruited from May 2020 to May 2021. Tools: I: Nurses' characteristic; II: Pre- post-test: about nurses’ knowledge regarding oxygen therapy and III: Observational checklist regarding nurses’ skills for caring neonates on oxygen therapy . Results: Most participants were males , more than half had Bachelor degree. Their mean age was twenty six years old, and more than third quarter of them had less than five years experience in NICUs, there were statistically significant differences regarding the total mean score of nurses’ knowledge and skills throughout the intervention phases. The lowest number of nurses who got a satisfactory level of knowledge and skills were at the pre intervention phase while all of them got a satisfactory level in post-and follow-up phases. Study intervention was the main statistically significant independent positive predictor of the skills score. Also, experience years, age and knowledge scores were a significant predictor of the skills score. Conclusion: The findings of this study strongly support the effectiveness of the designed guidelines about oxygen therapy for neonates in improving nurses' knowledge and skills. Recommendation: Integrate the designed guidelines of oxygen therapy for neonates in NICUs protocol for nurses.