Background: Discharge plan is a key element in patient with cardiac catheterization care. Aim: This study aimed to assess the informal caregivers' knowledge and practice regarding discharge plan for post cardiac catheterization patients. Research design: Descriptive research was used in this study. Sample: Convenience sample of informal caregivers having post cardiac catheterization patients was included 100 informal caregivers. Setting: It was conducted in cardiac catheterization Department in Tamia general hospital in El-Fayoum governorate, Egypt. Tools: One tool included four parts: First: Sociodemographic data for informal caregivers and patients, second: Past & current medical history of patients, third: Informal caregivers' knowledge, fourth: Informal caregivers' reported practice. Results: The study result revealed that, 63.0 % of the studied sample had poor knowledge regarding discharge plan for post-cardiac catheterization patients. 65.0 % of the studied sample had unsatisfactory with total reported practice regarding discharge plan for post-cardiac catheterization patients. Conclusion: The current study concluded that (63 %) less than two third of the studied informal caregiver had poor total knowledge about discharge plan for post-cardiac catheterization patients, also (65%) two third of them had unsatisfactory total reported practices regarding discharge plan for post-cardiac catheterization patients. There is statistically significant relation between studied informal caregivers' sociodemographic data and their knowledge, and reported practices regarding discharge plan for post-cardiac catheterization patients. Recommendations: Apply health education program for informal caregiver and design booklets about discharge plan for post cardiac catheterization patients to prevent further complications.