Summary With this competitive renewal application, we are seeking five years of support for a Training Program with the new Title of “Physician Scientist Training in Cancer Research” that has been continually funded since 1975. Since that time, more than 600 physicians and physician-scientists who were part of fellowship training programs in medical oncology received, through this funding mechanism, the essential support and protected time that they required to launch an academic career. Of the 117 trainees who have been supported by this T32 Award during the past 15 years, 13 continue as post-doctoral fellows in training. Of the remaining 104, 10 have left academia to pursue leadership positions in industry focused on cancer medicine, 6 are clinicians at major medical centers, 2 hold positions at the National Cancer Institute, and the remaining 86 are in academic positions including 2 Professors, 22 Associate Professors, 39 Assistant Professors, and 23 Instructors. Excluding fellows still in training, 90 former trainees of the remaining 104 have received external funding for their research including 37 that have been awarded an individual NIH K-type award. With the present application, we seek to continue this tradition of training the leaders in academic oncology. The future of cancer research will continue to depend on the continued training of highly-talented and creative physician-scientists who possess an understanding of the clinical aspects of neoplastic disease, are able to apply these concepts to appropriate laboratory studies within the many areas of tumor biology and emerge as academic leaders with sufficient skills to direct research programs, patient care, and educational efforts. The development of such individuals can only be accomplished within an environment where physicians and scientists work in physically adjacent areas, exchanging ideas and collaborating on a wide array of endeavors. The program will build on a foundation of excellence in Medical Oncology established during clinical training in the Dana-Farber/Massachusetts General Brigham Medical Oncology Fellowship Program. All of these candidates have already received an MD or MD/PhD degree, completed 2 or 3 years of Internal Medicine residency, and at least one year of clinical training in Medical Oncology. The training grant program will select the most highly qualified candidates from this pool who wish to pursue laboratory research or clinical investigation at the Dana-Farber Cancer Institute or nearby surrounding institutions. The program will provide outstanding mentored laboratory and clinical investigation research experiences from senior and experienced junior faculty and support for the recruitment and mentorship of under-represented minority fellows. It is expected that at the conclusion of their training, those individuals supported by this training program will have the ability to design, initiate, and complete individual clinical or laboratory research pr...