Background: In the posttransplant period, recipients face a complex phenomenon called the new heart, which is a symbol of physical and emotional life. They use different methods to get used to the new heart.Objective: The aim of this study was to explore the integration process with a donated heart in heart transplant patients.Methods: A qualitative study design with a grounded theory approach following Corbin and Strauss was used. Purposive and then theoretical sampling led to the inclusion of 15 heart transplant patients with diverse characteristics. Observations and semistructured interviews were conducted during a 1-year period in 2019 to 2020. Data collection and analysis occurred simultaneously.Results: The process of integration with the new heart in the transplant patients or the core category in this study was "rebirth." The process involved thre3 sequential and overlapping phases, which over time led to toleration and management of the situation. Religious issues, emotional chaos, additional worries, and sense of duality in the early stages after transplantation form a cycle, and the person is moving in this cycle.Discussion: The results of this study indicated that the patients experienced several emotional and psychological changes after heart transplantation. It was also shown that the participants experienced a change in the emotions and feelings over time. On the basis of the findings of this study, it can be suggested that health care providers need to improve their knowledge about posttransplant changes, recipients' feelings, and adaptation strategies.