Maintaining opiate addicts on opiates has a long history. The idea to prescribe pharmaceutical morphine as a substitute for street heroin started in USA and was abolished on the basis of prohibitionist legislation. A new approach to maintain opiate addicts on substitution therapy was initiated in USA in 1963, with the prescription of methadone. This approach found, although slowly, increasing acceptance, and is nowadays considered to be a cornerstone in the management of opiate dependence and for the prevention of HIV/AIDS in opiate injectors. Since 1975, the concept of heroin maintenance treatment was re-activated in order to reach out to treatment-resistant heroin addicts. Research projects were performed in Switzerland, the Netherlands, Germany, Spain, Canada and in England, another one is planned in Belgium. Based on the unanimously positive outcomes, heroin maintenance has become routine treatment for otherwise untreatable heroin addicts in Switzerland, the Netherlands, Germany and England, and Denmark has set up heroin maintenance without new research trials.