The National Heart, Lung, and Blood Institute (NHLBI) supports major research programs related to the field of transfusion medicine, which encompass blood banking, the practice of transfusion medicine itself, and cellular therapies. Specific programmatic elements have included 1) the Transfusion Medicine/Hemostasis Clinical Trials Network (TMH CTN) charged with conducting clinical trials in transfusion medicine and hemostasis; 2) the Retrovirus Epidemiology Donor Study-II (REDS-II), which includes domestic and international efforts dedicated to blood donor safety and blood availability issues; 3) the Specialized Centers of Clinically Oriented Research (SCCOR) in Transfusion Biology and Medicine that include two major projects, the Biologic and Immunologic Aspects of Transfusion Medicine Program and the Transfusion and Lung Injury Program, and 4) the Transfusion Therapy Trial for Functional Outcomes in Cardiovascular Patients Undergoing Surgical Hip Fracture Repair (FOCUS), a Phase III clinical trial that has as its major goal to determine whether a more aggressive transfusion strategy in surgery patients with cardiovascular disease (or risk factors) is associated with improved functional recovery and decreased risk of adverse postoperative outcomes. Notably, none of these programs supports epidemiologic and clinical outcomes research focused on transfusion recipients. Thus, on October 31, 2007, a Working Group on Transfusion Recipient Epidemiology and Outcomes Research was convened by the NHLBI. This group was asked to discuss the current status of the field, identify critical research needs, and make recommendations to the NHLBI program staff.