Background: Hematopoietic stem cell transplantation (HSCT) is a life-saving method for multiple conditions such as cancer, immune disorders, and hematologic diseases. Therapeutic regimen adherence in HSCT patients may be compromised by the complexity of their condition and could influence these patients' clinical outcomes, furthermore, non-adherence rises the risk of mounting serious health outcomes like graftversus-host disease, infection which all lead to readmissions. Aim of the study: The aim of this study is to identify the relationship between adherence to therapeutic regimen and clinical outcomes among patients post hematopoietic stem cell transplantation. Design and Setting: The study design was descriptive correlational research design. The study was carried out in the outpatient clinic of the Bone Marrow Transplantation Unit,