Background: Nursing surveillance is the key to patient safety as nurses can prevent iatrogenic harm and protect patients in intensive care unit(ICU)from medical errors done by others. Role of critical care nurses in patient safety is influenced by the specific requirements of the specialty which need continuous, close monitoring of the patient, dynamic data analysis and anticipation of complications.Aim of the study: to assess nurses' performance regarding implementation of patient safety in the intensive care units through assessing nurses' knowledge and performance regarding implementation of patient safety in the intensive care units.Research design: A descriptive exploratory design was utilized. Methods:Subject include all available nurses working in intensive care units in Damanhur Hospital, 50 nurses from both genders, with different ages, educational levels and years of experience was selected for this study. Data were obtained through two main tools: 1) Self-administered questionnaire tool, 2) observational checklist which divided to, patient unit observational check list and performance nurses observational check list. Results: Nurses had unsatisfactory knowledge and performance. There were statistically significance correlation between nurses knowledge and performance. Knowledge and performance were found to differ significantly in relation to socio-demographic data. Conclusion:More than half of the study nurses had unsatisfactory knowledge and performance regarding implementation of patient safety measures. Recommendations:The hospital should improve ICU safety structure and design andestablishing a protocol to ensure patient safety protocol will be implemented consistently in all ICUs. The study should be replicated on large sample & in different hospitals setting in order to generalize the results.