The article deals with the different approaches followed by the Turkish Constitutional Court and the European Court of Human Rights (ECtHR) in party prohibition cases. The Turkish Constitution and even more so the Law on Political Parties contain a long list of party bans, the violation of which leads to the closure of the party by the Constitutional Court. The Turkish Constitutional Court, both under the 1961 and the 1982 Constitutions, interpreted these provisions in an exceedingly illiberal manner, and has so far closed down a total of 24 political parties. Turkish rules and practices concerning the prohibition of political parties are among the most important 'democracy deficits' of the Turkish political system. In the article, the Turkish Court's illiberal approach to party prohibition cases, especially those involving the protection of the national and territorial integrity of the state and of the principle of secularism, is compared with the much more liberal criteria developed by the ECtHR and the Venice Commission.© 2010 Taylor & Francis.