Organizational ergonomics aspects, physical and mental task demands are considerable safety factors that can lead to poor performance and injuries in particular, health-care sector. This study aimed at identifying the main ergonomics factors that impact patient safety level and healthcare care workers performance. The descriptive analysis was used in this study using a questionnaire distributed to a 284 healthcare workers in a large hospital in Saudi Arabia including doctors after getting the consent form. The sample included three types of jobs; doctors, nurses and technicians to find the factors influencing patient safety and healthcare workers performance through NASA-TLX analysis results. The AHP technique was applied to determine the priority of five main ergonomic factors based on a second questionnaire to investigate the importance weights for each factor. The results of this study revealed that the organizational managerial factor was the most significant factor. Moreover, leadership was the most significant sub-factor from the operational managerial level. Team work was the most significant sub-factor from the workgroup/team level. Behavior was the most significant sub-factor from the individual worker level, mental load was the most significant sub-factor from the task work load level and finally radiation was the most significant sub-factor from the work environment level.