Background: Pulmonary embolism is the most important emergency in the cardiovascular system with a high rate of mortality without appropriate treatment. Aim: To investigate the effect of an educational program on critical care nurses' performance regarding pulmonary embolism emergency care. A Quasi-experimental design was utilized in this study. This study was carried out in the medical, surgical and emergency Intensive Care Unit at Al-Thawra Modern General Hospital Authority in Sanaa – Yemen. The sample of this study consisted of 75 nurses' for implementing the program. Tools utilized for data collection were the nursing questionnaire and observation checklist. The results There were statistically significant differences (P<0.000) in the total nurses, knowledge scores regarding emergency care for a patient with pulmonary embolism, pre-implementation of the program compared with the immediately post-implementation and post three months follow up. There were statistically significant differences (P<0.000) in total nurses, practice scores regarding emergency care for patient with pulmonary embolism pre-implementation compared with the immediately post-implementation and post three months follow up. Conclusion: There was a statistically significant difference between the nurse knowledge and practice in pre/post and follow up implementing of the educational program.