Background: The brain drain and resettlement of health professionals for better opportunities, both within countries and beyond universal boundaries, is a cause of increasing concern due to its resulting effects on health systems in developing countries over many years. Aim: This study aimed to assess nurses' awareness about brain drain and its determinants factors at Main Mansoura university hospital. Setting: The study was conducted at Main Mansoura University Hospital. Research design: A descriptive correlational research design was used. Subjects: Convenience sample of    nurses (195) was used. Tools:  Two tools were used namely: Brain Drain Awareness Questionnaire and Brain Drain Determinants Factors Questionnaire. Results:  The findings of the study revealed that nurses had good awareness about brain drain. The studied nurses had moderate perception of overall factors (push and pull) and there was a statistically significant strong positive correlation between overall brain drain determinants push and pull factors where and nurses' brain drain awareness. Conclusion: Both push and pull factors could independently contribute to a significant prediction of 65.2% and 66.7% of the nurses' brain drain awareness. Recommendation: Offering programs for professional growth and ongoing education, creating a supportive work environment and offering the necessary equipment and supplies.