This chapter examines the relationship between region and nation-building by focusing on the political dynamics of regionalism in Spain during the last quarter of the twentieth century, as well reviewing the theoretical and doctrinal aspects of regionalist discourses. Minority nationalism in the Basque country, Catalonia and Galicia has been a constant feature of twentieth-century Spanish politics. By examining the political evolution of Spanish regionalisms over the last two decades, an attempt is made at establishing the differences existing between regionalism and minority nationalism. To a certain extent these autonomist regionalisms are a new incarnation of pre-war regional movements, and, in fact, they reproduce some of the characteristics of historical regionalism present during the first third of the twentieth century. The proliferation of autonomist regionalisms in several autonomous communities determines contradictory relationships with the peripheral nationalisms and with the state. The chapter concludes that the state of the autonomous communities is still in progress, and not yet totally consolidated.