Background: A brain tumor craniotomy patients postoperative admitted to intensive care unit and need for regular monitoring of the overall condition during the first 48 hour so the critical care nurses play an important role in caring for patients of craniotomy, through Regular monitoring of the overall condition and reporting any deviations in health status during the first 48 hour after surgery. Aim of study: This study aims to assess nurses' performance for caring of patients during the first 48 hours post brain tumor craniotomy. Research design: A descriptive exploratory research design was utilized to achieve the aim of the present study. Setting: The current study was carried out in ICU at El Fayoum university hospital. Subject: Convenient sample of all available nurses approximately (40). Tools of data collection: First tool: Nurses' self-administered questionnaire to assess nurses level of knowledge regarding care of patients during the first 48hr post brain tumors craniotomy. Second tool: Nurses' observational checklist to assess nursing actual practice regarding care of patients during the first 48hr post brain tumors craniotomy Results: The results of this study revealed that 55% of studied nurses had a satisfactory level of total knowledge regarding the brain tumor craniotomy, while 45% of them had unsatisfactory level of total knowledge. And as regards the total practice 65% of them had a satisfactory level of practice, while 35% of them had unsatisfactory level of total practice. Conclusion: It more than half of studied nurses had a satisfactory total level of knowledge about care of Patients postoperative brain tumor craniotomy. And as regards the total nurses practice level post brain tumor craniotomy about two thirds of them had a satisfactory level of practice. Additionally there was no statistical significant difference relation between nurses total knowledge level and their different practice care level. Recommendations:  Providing continuous in-service education for nurses to update their knowledge related to nursing care for care of patient postoperative brain tumor craniotomy.