The increasing relevance of PMCs and PSCs is related to the progressive ‘privatization’ of war in all of its new expressions: the present scenarios of asymmetric warfare are characterised by the actions of non-State armed groups, which reject the traditional military and legally accepted methods of fighting The present analysis will first assess the type of work performed by private contractors: the focus will be on the real capabilities of the private sector and the challenges it poses. Then, it seeks the reasons for the recent growth of the private sector both in war and in peace-support operations. The point is made that the increased role of private companies in global security is undeniable and in many sectors necessary. With a serious quality certification, security clearance and transparent tendering, they should also be more reliable. Therefore, the issue is not what can be done and where can it be done by the PMSCs or indeed at what price, but how and to whom they must be responsible and accountable.