Donor is the person who donates stem cells in allogeneic stem cell transplant, wherein stem cells are collected from someone else.

Siblings are primarily screened in allogeneic stem cell transplantations for compatibility. If no related match donor can be found, screening is started for unrelated donors. Volunteers without contagious diseases, blood diseases, active viral diseases or chronic diseases should apply to bone marrow banks to become a donor. In this regard, the most important organization is TÜRKÖK that is directed cooperatively by Ministry of Health and Turkish Red Crescent, and all healthy people aged 18 to 50, who wants to donate blood stem cell, can be registered on this list, after 5 ml of blood is drawn and their tissue types are identified. After relevant data is recorded, the matching blood bone marrow can be needed at any location around the world. When this kind of need emerges, the donor candidate is called and asked if he/she still is volunteer to date blood stem cell. If the response is positive, transplantation procedure is carried out.