Medication administration errors are a significant concern in critical care settings due to the high acuity of patients and the complexity of their medication regimens. Several factors have been identified as contributing towards the incidence of medication administration errors among critically ill patients. Aim of the study: assess Nurses' perception of medication administration error to critical ill patients. Design: cross – sectional observational research design. Setting: The study was conducted at Intensive care units of Al-Rajhy hospital at Assuit university hospital. Sample: Convienence sample of all Nurses who work in the ICU 38 nurses. Tools: - Tool I: nurses personal data. Tool II: Nurses' perception of factors associated with medication administration error. Results: the result of current study showed that 86.84% of nurses was affected with workload, Regarding Physician related factors 73.68% Physicians change orders frequently Regarding medication related factors there are Polypharmacy 94.7%. Regarding Practice - related factors just 47.36% of nurses administer medication at the right time, Regarding Nurses' perception about environmental factors Lack of adequate staffing compared to the number of patients 97.3%. Conclusion: fatigue and workload of nurses, Lack of adequate staffing compared to the number of patients which reflected on administer medication at the right time to the patient and Polypharmacy presented as risk factors of medication administration errors Recommendations: Develop and implement protocol for nurses regarding factors associated with medication administration errors.