Project Summary This is a renewal application from the Columbia University's Vagelos College of Physicians and Surgeons for its postdoctoral training program in digestive and liver diseases. The program's mission is to train MD and MD/PhD trainees to become independent basic, clinical and translational researchers in gastroenterology and hepatology. The program has been in existence for nine years to date and has been highly successful in this mission. Trainees are selected from gastroenterology fellows in the Department of Medicine and Department of Pediatrics at Columbia. The gastroenterology fellowship programs in both Medicine and Pediatrics are diverse, highly competitive and put a primary emphasis on research training in both the selection and training of their fellows. This provides for an exceptionally strong pool of applicants to the training program. Furthermore, the training programs has succeeded in and will continue to recruit outstanding trainees from underrepresented minority groups. The program faculty is multidisciplinary and includes mentors not only in the Department of Medicine and Department of Pediatrics but also in other departments, institutes and centers at Columbia University. Most of the mentors are well-established, NIH-funded investigators but several early-stage junior mentors, who are paired with established mentors for training purposes, are also included. Trainees chose to pursue research in three broad thematic areas – 1) basic gastroenterology research, 2) basic liver research and 3) clinical epidemiology/precision medicine – and select a mentor in one of these areas. Trainees devote most of their effort to a mentored research project but also complete a rigorous program of didactic instruction, including, if they chose, the opportunity to obtain a master's degree in clinical research. In addition, strong emphasis is given to training in the responsible conduct of research and in rigor and reproducibility. Dr. Timothy C. Wang serves as Director of this training program and is ably assisted by Associate Directors Drs. Joel Lavine and Howard Worman. Each of these individuals have productive, active research programs and superb track records in postdoctoral training and medical education. The program is supported by both an Internal Advisory Committee of institutional leaders at Columbia and an External Advisory Committee of leading researchers in gastroenterology and hepatology at other institutions. The training program leverages other NIH-funded entities at Columbia University, including its Clinical and Translational Science Award program and educational programs within it. This training program will continue to produce exceptional physician-investigators in basic and clinical research in gastroenterology and liver diseases who will make significant contributions to our nation's public health.