Background: Critical care nurses are responsible for managing the preparation, timing of initiation, administration, titration, and weaning of vasoactive infusions based on the prescriptions of the physician so; to ensure patient safety, they must have adequate knowledge about medication, goals of drug therapy, and interventions to minimize adverse reactions. Aim of the study: This study was conducted to assess nurses' awareness regarding patients' safety receiving vasoactive medication in critical care units Design: A descriptive exploratory was utilized to achieve the aim. Setting: This study was conducted at two ICUs as follows (Cardiovascular Care Unit, and Chest Care Unit) affiliated with Ain Shams University Hospital. Sample: A convince sample (50) of all available nurses working in critical care units as mentioned previously. Tools: Data was collected using three tools 1) Nurses' Knowledge Interview Questionnaire.2) Nurses' level of Practice Observational Checklist.3) Nurses' Awareness of Medication Safety Scale. Results: The majority of the studied nurses had an unsatisfactory level of total knowledge and about a fifth had an incompetent level of practice. Meanwhile, most of the studied nurses had an unsafe level regarding patients' medication safety receiving vasoactive medication in critical care units. Conclusion: There was a statistically significant correlation between the total studied nurses' knowledge, practice, and their total patients' medication safety receiving vasoactive medication in critical care units. Recommendations: Provide educational and training programs to improve nurses' awareness regarding patients' medication safety receiving vasoactive medication in critical care units supported with evidence-based practices and guidelines. Keywords: Nurses' Awareness, Patients' Safety, Vasoactive Medication.