International Humanitarian Law (hereafter IHL) and International Human Rights Law (hereafter HRL) undoubtedly share some kinship. Yet, most international lawyers and judges, confronted with the simultaneous application of these two sets of norms have made a resort to the principle lex specialis derogat generali. Their use of that principle has presupposed that norms of IHL and HRL belong to the same legal order and the same legal regime and are, at the surface, in conflict with one another. This paper tries to rebut these presuppositions and showed that the relations between IHL and HRL ought to be construed in terms of competition rather than conflict. Drawing on the idea of competition between these two sets of rules, this paper subsequently seeks to evaluate the contemporary uses of the principle lex specialis derogat generali – particularly witnessed in the case-law of the ICJ – to calibrate the systemic integration of international law. It concludes that such an unorthodox use of that principle does little to alleviate the uncertainty inherent in the competitive character of the relationship between IHL and HRL.