PROPOSAL SUMMARY This T32 renewal proposes to continue its strong track record of postdoctoral training in Immunohematology and Transfusion Medicine initiated in 2001. The 6 position program provides a highly organized 2-3 year experience of focused dedicated didactics, seminars, and an intense research experience with one of 32 well- established, highly interactive, and well-funded cross-disciplinary mentors from nine different primary departments. The goal is to generate productive MD and MD/PhD physician-scientists as well as PhD scientists and clinician-scientists, who are launched on a lifelong investigative career pursuing basic, translational, and clinical research in this relatively underrepresented field. We propose to expand the training program to include 2 MD/PhD and PhD predoctoral students, who will also benefit from the unique training opportunities provided by this T32. Three major degree granting "tracks" are also available for MD post-docs: an Investigative Medicine PhD available to MD-only trainees who wish to obtain a more expansive research background mimicking that of an MD/PhD; a Master’s of Health Sciences for those with an emphasis on T3-T4 research; and a Masters of Biomedical Engineering for trainees with a past biomedicine emphasis who wish to add a diagnostic and cellular therapeutic engineering dimension to their career. Drawn predominantly from an MD, MD/PhD, and PhD candidate pool with a background focused on Laboratory Medicine & Pathology, with additions from adult and pediatric Hematology and Immunology/ID programs (a pool that has always included at least 10 fold more excellent, TG eligible, candidates than are accepted), outcomes have been quite positive. Of the 36 graduates of the T32 program over the past 15 years, there was an average of 4.5 papers and 2 first- author papers per trainee published as a direct result of the T32 training. Seven are still in training (e.g. clinical fellowship, ongoing research with independent K funding). Of the remaining 29, 96% (28) are in scientific careers; 41% (12) are in tenure-track research-intensive positions at research universities; 21% (6) in careers on the ladder research track at major universities, and 34% (10) are in senior scientist positions in industry.. As the only benign hematology T32 at Yale, one of the few Immunohematology/Transfusion Medicine T32s in the country that emphasizes PhD clinician-scientists (an important alternate career pathway for PhDs) along with MD and MD/PhD physician-scientists, and also one of the few postdoctoral hematology T32s that includes bioengineering and PhD degree tracks for MD-onlies, this program fills an important research training need both at Yale and nationally.