It is often thought that the concepts of jus cogens and international crimes walk hand in hand. After all, they both, appear at least to be about protecting basic values of the international community of States. Some even go as far as to assert that international crimes are, per se jus cogens. However, this piece will argue that this goes too far. Although there is a fair amount of substantive overlap, international crimes can exist outside of violations of jus cogens, and indeed pre-dated the acceptance of such a concept. Furthermore, through an evaluation of the jurisprudence of the ICJ and the ICTY, it will be argued that for the most part, no real additional consequences have been seen to flow from the jus cogens nature of violations of international criminal law, and where such consequences have been postulated (most notably in the Furundjžia case) these can be easily explained on other bases than jus cogens. It will conclude that in spite of frequent reference to the concept, especially in an academic context, it has not influenced States on point in any meaningful way.