Recent democratizations and state- and nation-building processes in post-communist Europe have promoted the new wave of salience of the nationalist cleavage in Europe with renewed agitation by minority groups and nationalist movements. This article deals in comparative perspective with nationalist parties, a specific type of party which has until now attracted little scholarly attention. After a brief explanation of the origins of the European nationalist and ethnoregionalist cleavages, the author analyses the different connotations euronationalisms and nationalist parties have taken through space and over time. He also attempts to explain why these minority and sometimes electorally irrelevant parties have on many occasions achieved impressive success with their policies: for example, the creation of a federal state in Belgium during the 1990s, the introduction of the devolution bills in the United Kingdom, the "velvet divorce" between Czechs and Slovaks. Another purpose of the article is to propose some criteria for a tipology of nationalist parties. The main difference the author stresses is between a traditional ethnocentric nationalism and the "new nationalism" of local and territorial entities and regions that feel more capable than distant bureaucracies in managing their affairs. The recent behaviour of minorities and their renewed political mobilization are probably symptomatic of broad changes in attitudes towards the territory and towards the existing States.