Background: Self‐care is an integral part of managing patients with heart failure. Extensive patient education on self-care is supported by the guidelines for the management of patients with heart failure. The aim of the study is to evaluate the effectiveness of Orem-Based Self-care Education on knowledge and Self-care behaviors among patients with Heart Failure. One group quasi-experimental Research design was used in this study. Setting: The Cardiology unit and Outpatient clinic at the Specialized Medical Hospital, Mansoura University Hospitals, Egypt served as the study setting. Sample: 65 patients were recruited to conduct the study. Three tools were used in data collection; Tool I: demographic and medical health status data, Tool II: Atlanta Heart Failure Knowledge Test, Tool III: The European Heart Failure Self-care Behavior Scale. Results validated the study's hypothesis since patients' mean scores of total knowledges improved statistically significantly (P<0.001) both immediately after and 1 month later compared to before receiving Orem-based self-care education. Furthermore, the mean scores of patients' overall selfcare behaviors improved statistically significantly with P<0.001 (1 and 3 months after Orem-based self-care education) compared to before. Conclusion: The application of Orem-based self-care education significantly improved the knowledge and, consequently, the self-care behaviors of patients with heart failure. Recommendations: The utilization of Orem's philosophy of self-care in self-care education by staff nurses working in cardiology departments is highly recommended.