The article outlines different `functions' of the International Criminal Court. The authors suggest that the ICC is more than just a criminal court proper adjudicating individual criminal responsibility. In addition, the Court should be regarded as a `watchdog court' monitoring its states parties' obligation to investigate, prosecute and punish international crimes, as well as a `security court' employed by the UN Security Council with the mandate to help restore international peace and security with regard to ongoing conflicts. The authors argue that the distinction between those three functions is important particularly for two reasons: First, in order to provide for sound benchmarks for assessing the Court's activity and, ultimately, its `success: Second, more specifically, the article identifies some tensions that might arise between these different functions of the Court. These tensions become apparent in various parts of the Statute, inter alia, as regards the application of the principle of complementarity, the exercise of prosecutorial discretion or the taking-into-account of amnesties.