Background: Pulmonary embolism is the third commonest cause of cardiovascular death after coronary artery disease and stroke .Preventing thrombus formation is a major nursing role. Therefore, the best management of pulmonary embolism is through prevention of risk factors. Aim: Assess nurses' performance regarding preventive measures of pulmonary embolism. Subjects and Method: A descriptive research design was used. Setting: The study was conducted in surgical department, orthopedic department and intensive care unit at Port-Said general hospital, Port-Fouad general hospital, and Elzohour hospital. Subjects: A convenient sample of 90 nurses were participate in the study Tools: Data were collected using three tools, Nurses' Knowledge questionnaire, observational check list for nurses' practice and Nurses 'attitude scale. Results: The result of study indicated that 71.1% of studied nurses had unsatisfactory knowledge, 62.2% had unsatisfactory practice and 74.4% had positive attitude regarding preventive measures of pulmonary embolism Conclusion:. The studied nurses had unsatisfactory level of knowledge and practice, but, remarkable positive attitude was observed regard the preventative measures of pulmonary embolism. Also there was statistical significant correlation between nurses' knowledge and practice .Recommendations: There are obvious needs for conducted an in service educational and training programs to improve nurses' performance regarding preventive measures of pulmonary embolism.