Several years after their establishment, the International Criminal Tribunals for Rwanda and the former Yugoslavia have reached the stage where sanctions will be imposed and subsequently must be executed by states. This article deals with practical and legal aspects of determining and enforcing the sentences, including: how and according to which rules enforcement will occur; which authority may pardon a convicted person and according to which criteria; and the extent to which pardon is a decision of political character. The highest sentence that the Tribunals can impose is life imprisonment and there is no special treatment for mentally ill persons. Court decisions of the Socialist Republic of Yugoslavia referred to war crimes committed during World War II, but it is much harder to have recourse to the general practice in Rwanda. In addition, there is an imbalance between the maximum penalty permitted to the Tribunals and the maximum penalty for genocide and other crimes in the relevant act of Rwanda, which provides for the death penalty in the most serious cases. Notes