Nowadays, private military and security companies (PMSCs) are playing an increasingly important role in armed conflicts. In this regard, there are relevant questions about the legality of their activities, as well as the ways of legal regulation. The article reviews the history of the appearing and functioning of PMSCs, analyzes the legal aspects which were developed by the international community aiming the ways of legal regulation of private and military companies, highlighted the most effective ways and means of regulating PMSC. In some research by foreign and Russian specialists covering PMSCs activities in areas of armed conflict, it is emphasized the existence of serious and, in fact, intractable problems of legal regulation of these commercial organizations that are currently operating in a legal vacuum that goes beyond international law, laws of contracting states and states of origin of PMSCs.An example of this can be the cases when the PMSC employees, being individuals working for remuneration, find themselves at the center of international scandals related to the executions of civilians, torture of prisoners, arms smuggling, child trafficking, mortality and other crimes. Taking into account the fact that Russia still has not resolved the issue of creating a legislative basis for regulating PMSCs, the author believes that as part of the work on solving the task posed by the leadership of our country to create a legislative basis for regulating the activities of PMSCs, it is more rational to analyze existing international legal instruments as well as foreign experience in the legal regulation of PMSCs, which, in turn, will contribute to solving the issue of the formation of a legal framework for the regulation of "private military power" in our country.At the same time, it is necessary to emphasize that high-quality legal support for the activities of PMSCs is a problem both of the states on the territory of which private military companies operate and of international law in general.The article reviews the history of the emergence and operation of PMSCs, analyzes the regulatory and legal framework developed by the international community in the field of legal regulation of private military and security companies, and highlights the most rational ways of regulating PMSC activities.