The Postdoctoral Fellowship Award supports exceptionally talented recent doctoral or medical graduates in pursuit of innovative, high-impact breast cancer research during their postdoctoral training and allows them to obtain the necessary experience for an independent career at the forefront of breast cancer research. Those individuals should be exceptionally talented scientists who have demonstrated that they are the “best and brightest” of their peers. Applicants for this award must exhibit a strong desire to pursue a career in breast cancer research. Under this award mechanism, the postdoctoral fellow is considered the Principal Investigator (PI) and, as such, should write the project narrative, training plan, and other application components with appropriate guidance from the mentor. While the PI is not required to have previous experience in breast cancer research, the proposed project and training must focus on breast cancer. Applications must emphasize the PI’s high potential for success in becoming an independent breast cancer researcher based on his/her qualifications, achievements (including first-author publications), and letters of recommendation. The mentor (or co-mentor, if applicable) must possess the appropriate expertise and experience in breast cancer, to include publications and active peer reviewed breast cancer funding, and clearly demonstrate a commitment to guiding the PI’s research and training. If the mentor is not an experienced breast cancer researcher, then formal co-mentorship by an established breast cancer researcher is required. The application must include information about the mentor’s experience in conducting innovative research and how he/she intends to support the PI’s endeavors in breast cancer. Mentorship by an investigator without an established record of mentoring pre- and postdoctoral trainees may be offset by the overall strength of the training plan. Applications must provide details on the suitability of the PI’s overall training plan and research project for attaining the goals of this award mechanism. Applications must elaborate on the qualities of the training environment in which the candidate will work, provide details on the individualized, breast cancer-focused training plan, and describe how this training will facilitate the PI’s career development as an independent, innovative breast cancer researcher. A multidisciplinary research approach to breast cancer is highly encouraged but not required; however, if there are multidisciplinary aspects to the training, they should be clearly outlined in the application. The application must articulate the potential impact that the proposed work will have on breast cancer. The research should be based on a sound scientific rationale and/or a thorough review of the literature. Preliminary data are not required.