PROJECT SUMMARY/ABSTRACT The Pediatric Hospital Epidemiology and Outcomes research Training (PHEOT) Program at Children’s Hospital of Philadelphia (CHOP) is a 2-year postdoctoral research fellowship designed to provide physicians with training in hospital epidemiology and outcomes research. The PHEOT program trains the next generation of physician scientists to best measure, investigate, and improve outcomes and patient safety for hospitalized children. Through a combination of formal coursework and mentored research projects, physician trainees develop expertise in comparative effectiveness research, exposure and outcomes measurement, severity adjustment, and decision analysis as they relate to pediatric hospital care. Five post-doctoral trainees simultaneously participate in the PHEOT program across the 2 years of training. Trainees benefit from the combined resources of two Centers at the CHOP Research Institute: The Center for Outcomes Research and the Center for Pediatric Clinical Effectiveness, as well as a rich array of “natural laboratories” for evaluating and improving health care processes and outcomes, including the Pediatric Advanced Care Service, the General Pediatrics Inpatient Service, the Center for Simulation, Advanced Education and Innovation, and the Center for Quality, Safety, and Analytics. All fellows complete Masters-level coursework in study design and biostatistics culminating in either the Master of Science in Clinical Epidemiology (MSCE) or the Master of Science in Health Policy Research (MSHP) degree at the University of Pennsylvania. Each fellow is assigned a mentorship team consisting of seasoned methodology, content, and biostatistics mentors who supervise the trainee in the successful completion and publication of at least one research project. PHEOT fellows also benefit from a host of professional development activities, including works-in-progress sessions, a weekly seminar series to teach academic medicine skills, and opportunities to present research at national meetings.