ABSTRACT Pain and substance use disorders (SUD) represent arguably the two most prevalent and costly public health condition in the United States. While vitally important to consider, the intersection of pain and SUD is not just limited to opioid use/abuse. Patients being treated for SUD (opioid and non-opioid) commonly report chronic pain, and, in turn, a history of SUD occurs frequently among patients who receive treatment for chronic pain. Despite the enormous need for new safe and efficacious treatments, the intersection of pain and SUD research remains a surprisingly underexplored area of inquiry, which has resulted in excessive knowledge gaps and limited pain treatment options for people with or in recovery from a SUD. To address this unmet need, we have developed a new postdoctoral training program: the Promoting Excellence through Pain and Addiction Research Enhancement (PREPARE) T90/R90 Training Program. A defining feature of the PREPARE Program will be an emphasis on social determinants of health (SDOH) as they relate to chronic pain and SUD clinical research. SDOH define the conditions in which people are born, grow, live, work, and age, and the inequities in power, money, and resources that are often responsible for disparities in pain and SUD outcomes across the U.S. Our overall goal is to develop outstanding independent investigators capable of sustaining productive clinical and translational research careers addressing the biopsychosocial (emphasis on social) mechanisms underlying chronic pain and SUD development, and/or designing clinical interventions to relieve pain and ameliorate SUD. To facilitate progress toward this goal, the PREPARE Program will complete the following. 1. Recruit and train promising early career investigators (postdoctoral fellows) to conduct mechanistically-based clinical research in pain and SUD. 2. Implement an integrated training program that will equip trainees with new research skills and the knowledge to apply these skills to important and unanswered questions regarding pain and SUD. 3. Create a culture of responsible research conduct and professional excellence to ensure trainees aspire to high standards of scientific integrity and quality. PREPARE will leverage an excellent infrastructure and collaborative network at the Washington University School of Medicine in St. Louis. We anticipate significant success in recruiting and training an outstanding and diverse group of trainees during the initial funding cycle. Members of the training faculty boast excellent track records of research funding and mentoring experience. Prepare requests support for five postdoctoral trainees (4 T90, 1 R90) from a variety of clinical training backgrounds, each of whom will work with their multidisciplinary mentoring team to create and implement a tailored independent development plan as the blueprint for their training. Trainees will achieve their research and career development objectives ...