Electrical cardioversion and defibrillation is a critical treatment for the survival of patients with cardiac arrest. Therefore, critical care nurses not only have to know how to monitor and operate the defibrillator, but also to provide interventions for preventing possible complications. The Aim of the present study was to evaluate the effect of educational program on knowledge and practice of nurses regarding defibrillation and cardioversion. Method A convenient sample of 50 nurses working in coronary care unit and emergency care unit at Assiut University Heart Hospital. A structured interview questionnaire sheet and Nurses practice observational checklist tools were used to collect the data. Results the present study revealed that total mean scores of the nurses knowledge and practices were improved from a preprogram level of (26.04 ± 9.51) to knowledge and (75.54 ± 10.90) for practice to an immediate post of (68.84 ± 1.75) for knowledge and (134.70 ± 1.52) for practice. Conclusion Nurses' level of knowledge and practice in caring of patients was unsatisfactory before the program and significantly improved immediately post program and at follow up phase in all items. Recommendation: Orientation program should be utilized for newly graduated nurses'