Background: Developmental care is a professional practice, education and research opportunity that nurses need to explore, evaluate and refine continuously within the rapidly changing technological environment of the Neonatal Intensive Care Units. Aim: This study aimed to assess nurses' performance regarding developmental care at Neonatal Intensive Care Units. Research design: A descriptive design was used. Setting: This study was conducted at the Neonatal Intensive Care Units of El-Fayoum General Hospital. Sample: A convenient sample that composed of 65 nurses who were working at the previously mentioned settings. Tools: A pre- designed questionnaire sheet, observational checklists and attitude-type rating scale to assess nurses' performance regarding developmental care at NICUs. Results: The majority of the studied nurses had poor level of knowledge, all of them were having an unsatisfactory level of practice and the majority of them showed positive attitude regarding developmental care at neonatal intensive care units. Conclusion: Nearly two thirds of the studied nurses had an incompetent level in total performance regarding developmental care at NICUs. Recommendations: Raising awareness about developmental care and its core measures in the care of neonates at NICUs.