Background: In critical care units, the utilization of medications is the cornerstone of patient care. Millions of lives can be improved and saved by using medications properly. Errors in the administration of medication in critical care units can have fatal consequences. Objective: To identify medication administration errors and their contributing factors from critical care nurses' perspective. Design: A descriptive research design. Settings: Six intensive care units at the Alexandria Main University Hospital. Subjects: A convenient sample of 176 critical care nurses with a range of educational backgrounds and at least six months of ICU experience. Tools: Two tools were used in this study. Tool one was the Medication Administration Errors Assessment. Part I: Nurses' sociodemographic and work-related data: Part II: Medication Administration Errors Assessment. Tool Two: Medication Administration Errors Contributing Factors assessment. Method: A structured interview was employed to collect data. Results and Conclusion: The study revealed that critical care nurses sometimes make medication administration errors, these errors include wrong rate, wrong interval, wrong dose, incorrect administration technique and other errors. These errors are attributed to various factors such as shortage of staff, lack of resources, and lack of reporting. Other contributing factors include years of experience, shift work, distractions, and inadequate knowledge. Factors like fatigue, psychological issues, and incomplete medical record information also contribute to errors. The study indicated a significant relationship between medication administration errors and nurses' age, sex, work experience, nurse-patient ratio. Recommendations suggestions: Implement medication administration training, follow policies, evaluate ICU nurse expertise, use technology, recruit professional staff, and ensure efficient medication administration to prevent errors.