This thesis examines prosecutorial challenges of the International Criminal Court (ICC/the court) in relation to the dwindling legitimacy prosecuting under Article 5 of the Rome Statute and other relevant international law principles. The study attempts a prognosis of the future shape of ICC prosecutions in light of the challenges and proposes reforms to the operations of the Court and its constitutive instrument to improve the dispensation of justice. The focus of the study is substantive international criminal law, developments in relevant case laws of international courts and tribunals, structure and procedures of the ICC and relevant principles within the context of elements of the Crime of genocide, crimes against humanity, war crimes and the Crime of aggression. The thesis further evaluates the role of the Court as it ensures international cooperation with domestic efforts to promote the ‘Rule of law’, uphold the principles of international humanitarian law, human rights law and combat impunity being the first permanent treaty-based international criminal court with the intent and purpose of ending impunity for perpetrators of the most serious crimes of concern to the international community and thus contributes to the prevention of such crimes. Additionally, the International Criminal Court advances international criminal justice, particularly with regard to victims by providing not only legal justice but also participation in the process and restorative justice to rebuild the society after mass violence. The thesis is an analysis of the prosecutorial challenges at the International Criminal Court, using its legal framework and jurisprudence to establish facts and reach new conclusions.