This thesis considers the fragmentation of international law as it affects the international human rights law, international humanitarian law and international criminal law regimes. It does this by examining the approaches of the three regimes to specific violations of the regimes' law. These are torture, enforced disappearance, sexual violence and the destruction of property. By this approach it is possible to see that while fragmentation is a very real phenomenon, the operation of the individual regimes is not impeded as some commentators have suggested. One way this is achieved is by each regime making a conscious effort to use legal rules particular to that regime in a formalised fashion. This seemingly restricts the operation of a policy-orientated approach to rule ascertainment, leading to a stronger and more cohesive body of international law.