Dr. Fiellin has focused his scholarly work on the interface between primary care, HIV and addiction. He is a primary care internist Board Certified in Internal Medicine and Addiction Medicine. He serves as the inaugural Director of the Yale Program in Addiction Medicine. He conducts research on the transfer of treatment strategies, including opioid agonist maintenance with methadone and buprenorphine, from specialized settings to office-based, primary care, Emergency Department and HIV specialty settings. He has served as Principal Investigator on multiple NIH-funded trials and directed the SAMHSA Physician Clinical Support System for buprenorphine. He is the Director of the Community Research and Implementation Core at Yale's Center for Interdisciplinary Research on AIDS. He has received awards including the Nyswander/Dole Award from the American Association for the Treatment of Opioid Dependence, the 2008 Annual Award from the American Society of Addiction Medicine, the Excellence in Mentorship Award from AMERSA and the Dan Anderson Research Award from the Hazelden-Betty Ford Foundation. He has served on the White House Office of National Drug Control Policy (ONDCP), Drug Control Research, Data, and Evaluation Advisory Committee, and the World Health Organization and United Nations Office on Drugs and Crime Technical Guideline Development Group for psychosocially assisted pharmacologic treatment of opioid dependence. He served as Chair of the Center for Substance Abuse Treatment's, Treatment Improvement Protocol on Treatment of Viral Hepatitis in Patients with Substance Use Disorders and on the Editorial Boards of Substance Abuse and the Journal of Addiction Medicine and is Co-Editor of Alcohol, Other Drugs & Health: Current Evidence and the Principles of Addiction Medicine, 4th, 5th and 6th Edition. He has served on the Board of Directors of the College on Problems of Drug Dependence and as Co-Chair of the Substance Abuse Task Force for the Society of General Internal Medicine.