Abstract Diabetic coma is a dangerous condition that can lead to unconsciousness and even death. There are three main causes of diabetic coma: diabetic ketoacidosis, severe hypoglycemia and hyperglycemic hyperosmolar state. Aim of the study: This study aimed to assess nurse`s knowledge and practice regarding patients with diabetic coma. Research design: A descriptive research design was utilized in this study. Sitting: This study was conducted in emergency Care Unit at Assuit University Hospital. Subject and Method: This study was carried out on a convenience 35 nurses who are working in emergency care unit. Tools: Tool 1: Nurses’ knowledge assessment tool.Tool 2: Observational checklist regarding care for patient with diabetic coma. Results: The results showed that (68.6%) of nurses had unsatisfactory level of knowledge regarding care of patient with diabetic coma and (94.3%) of nurses had unsatisfactory level of practices regarding care for patient with diabetic coma. Conclusion: Nurses showed inadequacy of their knowledge regarding care of patients with diabetic coma. Recommendation: The study recommends that there is a need for an education program regarding care for patients with diabetic coma.