Background: Venous thromboembolism in the form of deep venous thrombosis and pulmonary embolism is a leading cause of hospital related deaths worldwide with range between 10 and 30% and associated with additional morbidity and mortality. Aim of the study: Was to evaluate the effect of an educational program on nurses' performance regarding prevention of venous thromboembolism among critically ill patients. Design: Quasi experimental research design was used to achieve the objective of the current study. Setting: This study was conducted at Benha University Hospital in intensive care units (General, Coronary and Critical Care Unit). Sample: Convenient sample of 120 nurses included in the study. Tools: Two tools were used, I: An interview questionnaire to assess nurses' knowledge regarding prevention of venous thromboembolism, it consisted of two parts, part1: Demographic data for nurses, part 2: Nurses' knowledge related to venous thromboembolism and II: Observational checklist for the evaluation of nursing suffering from venous thromboembolism. Results: Majority of the nurses had unsatisfactory knowledge and practice regarding prevention of venous thromboembolism pre intervention program (72.5% and72.5%) respectively which improved immediately post program intervention to (65.8% and78.3%) respectively as (P ≤ 0.001). Conclusion: The educational program has positive effect in improving nurses' performance (knowledge and practice) regarding prevention of venous thromboembolism among critically ill patients. Recommendations: Conducting continuous educational and training programs for nurses regarding prevention of venous thromboembolism among critically ill patients.