Guidelines which have been laid down by the most authoritative international organizations are presented. The author also criticizes the limits of the reform, which in his view, has not taken adequate account of the current degree of social 'undesirability' of most of the decriminalized types of behavior, and has not examined the advisability of using suitable mechanisms for totally decriminalizing them. In these terms, the author illustrates the findings of an international group of experts from the Council of Europe, which has compared the legislation and practice of all the countries that belong to the Council, and has suggested practical models for decriminalization that could be used uniformly in all European countries. (Author summary modified)