The number of allogeneic hematopoietic SCTs performed globally each year continues to increase, paralleled by an increased demand for donors of therapeutic cells. Donor characteristics and collection procedures have undergone major changes during recent decades, and further changes are foreseen. Information on short- and long-term donor outcomes is of crucial importance to ensure maximal donor safety and availability. Current data, predominantly from unrelated donors, give reliable information on the frequent early events associated with donation-most of them of mild-to-moderate intensity. Information on the type and relative risk of serious adverse reactions is more limited. Moreover, only few data exist on long-term donor outcome. On the basis of this need, recommendations for a minimum data set for prospective donor follow-up were developed in a workshop with the participation of an international group of investigators actively involved in allogeneic stem cell donation under the auspices of and approved by the Worldwide Network for Blood and Marrow Transplantation. Establishment of a standardized global follow-up for both, related and unrelated, donors will enable monitoring of the short- and long-term safety profiles of hematopoietic cell donation and form a solid basis for future donor selection and counseling.