The World Marrow Donor Association (WMDA) fosters collaboration between international registries to facilitate the exchange of hematopoietic stem cell products for unrelated stem cell donor transplantation. As indications for hematopoietic SCT grow, the movement of products across the world will increase. Although competent authorities may regulate products within their country, there is a need to protect the best interests of donors and recipients by identifying universal donor medical suitability criteria. Within this report the WMDA provides a background to unrelated adult donor and recipient safety, recommends a common framework for assessing the health of unrelated adult donors at each stage of the donation pathway and presents a novel mechanism for sharing international consensus criteria for individual medical and lifestyle conditions. Wherever possible, these criteria are evidence-based. By establishing a donor medical suitability working group, the WMDA has developed a process through which donor centers and registries may request a consensus opinion on conditions not already listed, as well as challenge existing criteria. Guidance from the WMDA is intended to complement, not supersede, guidance from national competent authorities and international regulatory bodies.