Buprenorphine is an opioid mixed agonist-antagonist that has potential usefulness as a pharmacotherapy for opiate addiction. Buprenorphine significantly suppressed opiate self-administration by heroin addicts. Buprenorphine also suppressed opiate self-administration in a primate model. Although buprenorphine is a positive reinforcer in rhesus monkey, it is less reinforcing than other opioids and some opioid mixed agonist-antagonists as evaluated in progressive ratio and drug substitution procedures. These data suggest that the abuse liability of buprenorphine should be less than that of other opioid drugs. The safety and potential therapeutic benefits of buprenorphine relative to other currently available pharmacotherapies probably overweigh the possible risks of abuse.