This article focuses on the definition of transnational crime, as well as on the identification of the causes and conditions of transnational crimes. On the example of illegal sale of narcotic substances at the international level, the authors attempt to make a comprehensive analysis of the characteristics of transnational crime at the present stage of development of the international community.?Authors conclude that domestic methods of detection of transnational crimes are outdated and are not able to fully meet the needs of the investigation. Confronting transnational crime, which is complex in nature, requires interaction between the entire world community and individual regions. Cooperation between the European Union and Russia as the largest participants in international relations is particularly important. Despite the established regulatory framework for combating organized crime, in particular drug trafficking, there are problems that require immediate solutions. It should be noted that the need for work on which it is necessary to intensify in the near future: the development of a unified anti-drug policy, the harmonization of national legislation, the development and implementation of international operations to control narcotic and psychotropic drugs in legal circulation, further exchange of experience on drug demand reduction, prevention, treatment and rehabilitation of drug patients.