The advent of the principle of complementarity under the Statute of the International Criminal Court has shifted the focus on prosecuting international crimes to the national courts. One of the potential difficulties in this shift is that there is no uniform standard for incorporating and applying international legal norms in the national systems. This article examines how two very distinct national courts – the state Court of Bosnia and Herzegovina and the military courts of the Democratic Republic of Congo – have implemented and applied international legal norms. Despite the differences between these particular courts in the methods of implementation and application, international courts have had an impact on the national systems that have helped the latter to follow international criminal legal norms.