Background :Management of third stage of labor one of the most important nursing care which help in preventing postpartum hemorrhage and prevalence of maternal mortality and morbidity among women. Aim: Evaluate the effect of nursing care protocol on nurses' performance during third stage of labor. Subjects and method: Design: A quasi- experimental study wasadopted. Setting: The current study was conducted at labor units in 3 hospitals in Port-Said city, General Port Said hospital, Obstetrics and Gynecological Specialized hospital and Port-Fouad hospital. Subjects:A total of fifty nurses. Tools: Three tools wereused for data collection: 1-Structured Self -administered questionnaire,2- Knowledge assessment tool and 3- An observational checklist. Results:Most of the studied nurses had unsatisfactory level of knowledge and practices regarding management of third stage of labor in pre intervention and most of the studied nurses had satisfactory level of knowledge and practices in post and follow up intervention. Conclusion:The protocol of care had positive effect on nurses' knowledge and practices regarding third stage of labor. Recommendations:Periodicalin service training educational programs for nurses working in obstetrics and gynecology departments in different hospitals to upgrade their knowledge and practice regarding third stage of labor.