Hematopoietic Stem Cell Transplantation (HSCT) is a life-saving procedure used to treat various blood disorders, cancers, and immune deficiencies. It involves the infusion of healthy hematopoietic stem cells to restore bone marrow function after chemotherapy or radiation. HSCT can be autologous (from the patient) or allogeneic (from a donor). Success depends on factors like donor match, patient condition, and post-transplant care. Ongoing research aims to improve outcomes and reduce complications such as graft-versus-host disease.