The request for blood donations has been progressively increasing over the last several years, as a necessary complement to major surgical operations and the cure of severely affected individuals. Being a major hospital where every day hundreds of people are admitted to the emergency room or subject to surgical operations, the San Raffaele needs large daily supplies of blood products. This major need can only be satisfied thanks to the generosity of blood donors, as blood-derived products cannot be produced artificially. Blood donors are most welcome at the San Raffaele Blood Centre, where they undergo a free and comprehensive screening of their general health condition and hematological parameters during each blood donation. Some hematological disorders, including selected leukemias and aplastic anemias, can undergo clinical remission, and sometimes be cured, exclusively through bone marrow transplantation. Bone marrow donors are atypical, in that they donate on demand, whenever genetically compatible patients are in need of a graft. Bone marrow donation involves some discomfort of the donor, but nowadays is a totally safe procedure. Blood and bone marrow donors are an invaluable asset for the San Raffaele Hospital, and over the years they have contributed in a major way to save hundreds of people's lives.