The present work seeks to analyze the regulatory system of private military and security companies, the PMSCs, for their actions in international conflicts. The debate on the PMSCs first deals with the distinction between these entities and mercenaries, which are considered illegal. Thus the first part of the research deals with the legal situation of the PMSCs and the differences between them and traditional mercenaries, concluding that these companies are not in a gray zone of International law. The following are analyzed the regulatory systems that these companies are subject to and proposals to curb human rights violations in their operations. The system of self-regulation is compared to international regime regulations, which are deployed from international regimes for mercenaries. From analyzing the development of the market for PMSCs the work proposes a certification based in human rights to be integrated in self-regulation as the most adequate response to deal with the dynamism in the current industry.