Background: Diabetes Mellitus has affected humans for many decades, and the descriptions of it are amazing important, which it's incidence is rising abruptly worldwide, Nowadays, the introduction of new insulin formulations and a new emphasis on tight blood glucose control make inpatient diabetes treatment has become more complicated, and it requires very careful monitoring by the nursing staff, while expanding their knowledge and practical skills to prevent dangerous side effects when giving insulin to patients. Objectives: The study aims to assess the nurse's knowledge and awareness regarding Insulin Therapy for Diabetic Patients in the emergency department at Al Diwaniyah Teaching Hospital, and finding the association between demographic data which as the gender, educational level, years of experiences in the emergency department, and training course and their level of nurse's knowledge. Materials and Methods: Descriptive study has been carried out to assess the nurse's knowledge and awareness regarding insulin therapy for diabetic patients in the emergency department at Al Diwaniyah Teaching Hospital for the period from 16 of January 2022 to 10 July of 2022. A purposive sample of (50) nurses who work in the emergency department at Al Diwaniyah Teaching Hospital. A questionnaire format was constructed to assess the knowledge of nurses about insulin therapy for diabetic Patients in the emergency department at Al Diwaniyah Teaching Hospital.The questionnaire was divide to two main parts: First Part: Demographic data of the sample include (Age, Gender, Educational level, Duration of work as a nurse, Years of experiences and training courses regarding management of diabetic patients and insulin therapy. Second Part: This part include 18 multiple questions to assess the knowledge of nurses and awareness about insulin therapy for diabetic Patients in the emergency department at Al Diwaniyah Teaching Hospital. Results: Results of the study shows the highest of nurses’ knowledge items are (Moderate). While (Bad) was the main nurses’ knowledge regarding to store insulin and perform a physical assessment to establish a baseline before beginning therapy. The majority of nurses 77.8% of nurses' knowledge have Moderate, while 11.1% of them have Bad and 11.1% of them have (Good) regarding to overall Assessment of nurses’ knowledge, there are a highly association between education level, and years of experience about management of diabetic Patients undergoing insulin therapy in the emergency department. Conclusion: The study concluded that the highest of nurses’ knowledge items are (Moderate). While (Bad) was the main nurses’ knowledge regarding to store insulin and perform a physical assessment to establish a baseline before beginning therapy. Also there are a highly association between level of education, and years of experience about insulin therapy for diabetic patients in the emergency department and their efficacy of nurses’ knowledge. Recommendations: Increasing the knowledge and awareness of nursing staff concerning insulin therapy for diabetic patients by improving training courses. Also establishing education programs to improve nurses' knowledge and awareness toward the newest issues related to insulin therapy in the emergency department.