Although the concept of impunity in a first approach has been usually translated as the simple absence of punishment or lack of penalty, it is true that this concept involves much more than that; in fact its content is in a permanent state of development and expansion. The purpose of this paper is, therefore, to offer a systemic and updated research of the impunity concept. In this sense, this study, firstly, will be focused from the point of view of International Crime Law, including proper mentions of International Humanitarian Law. From this first point of view, it will follow an idea of impunity very close to the absence of crime penalty. Later on, the research will analyse the concept from the point of view of the International Human Rights Law, at which time we will realize that the essence of this concept goes beyond the purely punitive. Finally we will try to synthesize both approaches in order to offer a comprehensive and systemic conception of impunity from the Public International Law standpoint.