Over the past several years exciting developments arising from clinical and basic research studies have allowed much deeper insight into the mechanisms and consequences of blood group alloimmunization. These developments have direct implications in the prevention of alloimmunization. Thus, the purpose of this session will be to: 1) update participants on the risks of blood group alloantibodies and 2) discuss proactive strategies for the prevention blood group antigen alloimmunization. Speakers will present the most recent clinical data regarding alloantibody induction/evanescence and implications of these processes in delayed hemolytic transfusion reactions, antigenic immunogenicity, and transfusion-associated morbidity. Next, data gleaned from novel animal models of blood group alloimmunization will be presented to show those factors that most influence the development of alloantibodies and how control or avoidance of these factors may reduce the potential for immunization events. Finally, the role of molecular genotyping in immunohematology will be presented with an emphasis on recent findings from clinical and basic science literature.