Heroin-dependent men were given buprenorphine (a partial opiate agonist-antagonist) or a placebo under double-blind conditions on a clinical research ward where they could acquire heroin (21 to 40.5 milligrams per day, intravenously). Buprenorphine significantly (P < .001) suppressed the self-administration of heroin over 10 days. Control subjects took between 93 and 100 percent of the available heroin. The effects of buprenorphine were dose-dependent; a dose of 8 milligrams per day reduced heroin use by 69 to 98 percent; a dose of 4 milligrams per day reduced heroin use by 45 percent. Termination of buprenorphine maintenance did not result in opiate withdrawal signs or symptoms. The subjects liked buprenorphine and indicated that it was preferable to methadone or naltrexone. Buprenorphine should be a safe and effective new pharmacotherapy for heroin dependence.