PROPOSAL SUMMARY This proposal is for renewal of our postdoctoral research training grant in Immunohematology and Transfusion Medicine that was initiated in 2001. The six position program provides a highly organized 2-3 year experience of focused dedicated didactics, seminars, and, most importantly, an intense research experience with one of 29 well-established, highly interactive, and well-funded cross-disciplinary mentors representing eight different primary departments. The goal is to generate productive MD and MD/PhD physician- scientists as well as PhD scientists and clinician-scientists, who will be launched on a lifelong investigative career pursuing basic, translational, and clinical research in this relatively underrepresented field. Careful career development by an individualized "Training and Career Advisory Committee" is a hallmark of the program. Two major degree- granting "tracks" are also available in addition to the core post-doctoral program: an Investigative Medicine PhD available to MD-only trainees who wish to obtain a more expansive research background mimicking that of an MD/PhD; and a Masters of Biomedical Engineering for trainees with a past basic biomedicine emphasis who wish to add a diagnostic and cellular therapeutic engineering dimension to their knowledge base. Drawn from an MD, MD/PhD, and PhD candidate pool focused on those whose background is Laboratory Medicine & Pathology (a pool which has always included at least 10 fold more excellent, training grant eligible, candidates than can be accepted into the T32 program), outcomes have been quite positive. Of the 21 graduates of the T32 program over 15 years, there was an average of 4.2 papers and 2.2 first-author papers per trainee published as a direct result of the T32 training and all 21 graduates have published papers in the last three years as a result of their continuing scientific careers. All are in scientific careers; 48% are in tenure-track research-intensive positions at research universities; 19% in careers on the ladder research track at major universities, and 21% are in senior scientist positions in industry. The "core" T32 is "leveraged", that is, the entire enrollment in the Laboratory Medicine Departmental Immunohematology-Transfusion Medicine research training program is greater than the T32-funded individuals alone by about 50%, since the extended program includes individuals on other funding mechanisms sharing the same infrastructure. Including trainees in the extended program, there are 63% University tenure-track faculty, 13% University research track faculty, and 19% in senior scientist positions in industry. As the only benign hematology T32 at Yale, one of the few Immunohematology T32s in the country that emphasizes PhD clinician-scientists along with MD and MD/PhD physician-scientists, and also one of the few postdoctoral hematology T32s that includes bioengineering and PhD degree tracks, this program fills an important research training ne...