This article examines under what conditions descriptive representatives of national minorities can also act as substantive representatives. It provides an empirical analysis of the behaviour of the representatives with ethnic minority backgrounds in the eighth National Assembly of the Republic of Serbia. Specifically, the article builds upon a content analysis of all interventions in the plenary parliamentary debates of the thirtyone minority MPs in the period between June 2008 and March 2012. The analysis suggests that having a minority ethnic background or political party registered as a political party of national minority are not sufficient conditions for substantive minority representation. The findings show that minority representatives elected on minority electoral lists engage more in substantive representation of minorities than descriptive representatives elected to parliament either as members of mainstream parties or through pre-electoral arrangements of minority parties with mainstream political parties.