In the middle of 20th century a new phenomenon appeared in Western Europe and Scandinavia, parallel to the construction of a united Europe: the constitution of cross-border regions and their institutionalization by means of cross-border cooperation. Since then dozens of cross-border regions have appeared, especially since 1990, which for the most part fall under the denominations of euroregion, working community or eurodistrict. Their territorial distribution also has been increased, and at present there is virtually no substate border authority that does not take part in some cooperation initiative. In the article, first, an inventory previously elaborated (Perkmann, 2003) is updated; then an approach to the history of the regionalization of cross-border cooperation in Europe (1958-2007) is drawn, in which three great stages are distinguished; and, finally, there is an analysis of the characteristics and distribution of the cross-border regions.