Background: Preterm infant is a live born infant delivered before 37 completed weeks of gestation. Prematurity is responsible for the largest number of admissions to neonatal intensive care unit (NICU). Family centered developmental care (FCDC), is defined as a group of nursing interventions formulated to reduce the effects of the NICU environmental stressors on preterm infants, and integration of family in their infants' care in order to improve outcomes of preterm infants, and their families. Neonatal nurses are in a unique position to implement neuroprotective interventions. Aim of the study this study was done to evaluate the effect of implementing an educational program about FCDC on neonatal nurses' knowledge and practice. Design: A quasi experimental research design using (pre- test & post-test measures) was used. Method: The study was conducted at the NICUs related to El-Mansoura General Hospital and El-Mansoura New General Hospital at Mansoura City, Egypt. The study included all nurses (=51), recruited over six months' period. Two tools were used to collect data; nurses' knowledge about family centered developmental care structured questionnaire, and nurses' practices of family centered developmental care observational checklist. Results: The finding of this study showed that, the minority of nurses (13.7%) had sufficient knowledge about FCDC before the program implementation, the percentage was improved to 100% immediately after the program, and at follow up In addition, the FCDC program implementation resulted in significant improvements in nurses' practices from totally unsatisfactory before the program implementation to 100 % satisfactory immediately after and slightly declined to 95.7% at follow up phase and the difference was statistically significant at p=0. 000. Conclusion & recommendations: it was concluded that the educational program has positive effect on nurses' knowledge and practice regarding FCDC. The study recommended including FCDC interventions into nurses' curriculum and creates developmental care team with physicians, and nurses to follow the application of family centered developmental care. As well as assessing mothers' barriers that hindering them from being a part of their preterm infant life at NICU. In addition, continuous training is essential to change the attitude of medical team toward including family in care plan for the preterm infants.