knowledge and attitudes can directly influence their practices. Effective nurses' practices lead to achievement of the desired outcomes. The study aimed to: assess Nurse's Knowledge and attitude regarding WHO breastfeeding guideline during COVID-19. Subject & Method: A descriptive research design was used to accomplish this study. Sample: Study sample included one hundred and ten nurses who were working in obstetrics and gynecology departments and neonatal intensive care unit at Mansoura University Hospitals were involved in the study. Tools: Data was collected through three tools. Tool I: Socio- demographic data about nurses. Tool II: Nurse's Knowledge regarding WHO breastfeeding guideline during COVID-19.It included 2 parts: Part I: General knowledge about covid 19: Part II: knowledge regarding WHO breastfeeding guideline during COVID-19.Tool III: Attitude of the nurses towards breast feeding during COVID‐19. Results: A total of 71 (64.5%) of nurses showed poor level of knowledge regarding World Health Organization breastfeeding guideline during COVID-19, while 12 (10.9%) of nurses had good level of knowledge. Moreover, 65.5% of nurses had a positive attitude toward breast feeding during COVID-19. Conclusion: The study provided a better understanding of prevalent knowledge of nurses regarding the recommended breastfeeding practices among suspected or confirmed cases with COVID-19. The results highlighted that there were poor knowledge score regarding WHO breastfeeding guideline during COVID-19 and a positive attitude toward breast feeding during covid. The study recommended; Promotion of optimal breastfeeding practices during the COVID-19 pandemic and creating awareness among nurses and HCWs about WHO breastfeeding guideline during COVID-19. Further researches; are needed to provide educational program to nurses about World Health Organization breastfeeding guidelines during COVID-19