Taking as a point of departure Mary Douglas' grid-group analysis, elaborated on by Aaron Wildavsky in his cultural theory, the article explores the variations in the development of methadone treatment programmes in the Nordic countries from the mid-1960's to the mid-1990's. In Sweden, the first Nordic country to start an organized treatment of heroin addicts with methadone in 1966, the strategy has been characterized by many rules and strong control. In Denmark, methadone treatment was introduced in the late 1960's, and it has been characterized by few rules and weak control. In Norway, methadone treatment was banned in 1979, after some years of occasional experiments. But the spread of HIV among intravenous heroin addicts altered the attitudes and a small and highly regulated program was set up in the beginnings of the 1990's. In Finland, the attitude has been reserved, primarily due to the small population of heroin addicts. The organized treatment in the 1970's was limited, and still is, as it was set up again in 1995. In spite of the differences, however, there are two main patterns of harmonization that should be noticed. Firstly, as a result of HIV, regulated programmes have been developed in all four countries in the 1990's. Secondly, the prevailing abstinence-oriented philosophy has been questioned and supplemented by harm-reducing measures. Today, there is a stronger tendency to treat drug addicts as clients in the Nordic welfare state, entitled to individual treatment in the countries' general health and welfare systems.