PROJECT SUMMARY/ABSTRACT This is the fourth competitive renewal for T32DA013911 (HIV and Other Infectious Consequences of Substance Use) and seeks funding for Years 21-25. The program is led by multiple PIs: Dr. Timothy P. Flanigan (the PI for the past 20 years), who will direct mentoring and training, and Dr. Josiah D. Rich (MPI for the last cycle), who will direct research project development. This training grant focuses on applied clinical and substance use research in Rhode Island and beyond. Rhode Island has among the highest rates of substance use in the nation and ranks 6th in the country for overdose rates. Our substance use training program emerged from the Brown University-affiliated Miriam Hospital Immunology Center, the largest HIV care center in Southern New England, where approximately 60% of the patients engage in substance use (alcohol, cocaine, opioid, methamphetamines, and poly-substance abuse). Our program’s strengths are our interdisciplinary collaborations to reduce the infectious disease consequences of substance use, including HIV, hepatitis B and C, sexually transmitted infections, and TB. This training program brings together core expertise from the Division of Infectious Diseases, the Providence-Boston NIH funded Center for AIDS Research (CFAR), the NIH-funded COBRE Center on Opioids and Overdose, the Centers for Behavioral and Preventive Medicine, the Brown University Center for Statistical Studies, and the Brown University School of Public Health. This interdisciplinary training program focuses on HIV prevention and treatment, including innovative PrEP programs, and correctional health, with a primary focus on reducing the infectious consequences of substance use as well as overdose. Our mentors have strong track records in applied clinical, substance use, translational science, correctional health research, and community-engaged scholarship.