Substance use and substance use disorders (SUD) constitute major public health problems due to their associated disability, comorbidity and mortality. Addressing these burdens requires cutting-edge public health research conducted by scientists of the highest caliber. In 2012, the Substance Abuse Epidemiology Training Program (SAETP) at Columbia University Irving Medical Center (CUIMC) in New York City was established with the objective of training talented young scientists to become the next generation of leaders in substance abuse epidemiology. Through competitive applications, SAETP has successfully, attracted a diverse group of fellows that have been productive and successful during and after training. Completed SAETP fellows have attained prestigious research positions in academic research settings and many have obtained their own independent funding. We now propose the next 5-year renewal cycle for SAETP. SAETP exists in a very rich, stimulating environment, offering unparalleled academic medical center resources. With its specialized training for substance abuse epidemiology careers, SAETP is unique at CUIMC. Dr. Deborah Hasin and Dr. Silvia Martins, SAETP MPIs, are internationally recognized substance abuse epidemiologists with extensive successful mentoring experience. The 24 other SAETP faculty members offer interdisciplinary expertise (e.g., epidemiology, psychiatry, psychology, sociomedical sciences, biostatistics, nursing) and have outstanding records of publishing, funding, collaborations, and mentoring productive and successful trainees. At any given time in the renewal, SAETP will continue to train 4 pre-doctoral fellows for training periods of 3-5 years each, and 4 post-doctoral fellows for training periods of 2-3 years each, a number that has worked well in the current cycle. Fellows will be selected based on their prior accomplishments, commitment to substance abuse epidemiology careers, and fit with the SAETP program. Recruitment efforts to enroll under-represented minority trainees have been successful, with 33% of SAETP fellows from such groups to date (50% currently); we will continue these recruitment efforts. SAETP will provide broad, intensive training in substance abuse epidemiology and related areas; depth in one or more areas of specialization; cutting-edge methodological skills, development of conceptual skills, including formulation of key research questions and testable hypotheses, and the ability to design and conduct high-quality substance abuse epidemiology studies. Fellows will receive mentoring and participate in many training components, e.g., weekly substance abuse epidemiology faculty-fellow seminars, research internships, academic courses. Fellows will also receive training in the Responsible Conduct of Research and Rigor and Reproducibility in Research. SAETP training will enable fellows to publish papers, hone presentation skills, learn to write fundable grant proposals, and enhance collaboration and lea...