Pharmacotherapy for substance abuse is a rapidly evolving field comprising both old and new effective treatments for substance use. Opiate agonist therapy has been shown to diminish and often eliminate opiate use. This behavior change has resulted in the reduced transmission of many infections, including HIV, hepatitis C virus (HCV), and an enhanced quality of life. For the past 35 years, the provision of opioid agonist therapy has been limited to opioid treatment programmes. Opioid treatment programmes treat approximately 200 000 of the estimated million opiate-addicted individuals in the United States. With the need to increase the number of treatment opportunities available for opioid-dependent patients, Congress passed the Drug Addiction Treatment Act of 2000, which allows for the treatment of opioid dependence using buprenorphine by a properly licensed physician, including HIV primary care physicians. The integration of buprenorphine treatment for opioid addiction into HIV primary care thus provides a new treatment paradigm to address substance abuse in patients with HIV and HCV infections.