This article tries to point the maximum social and political impact of the urban social movements in Barcelona and its metropolitan area. The triennium 1975-77, which frames were two key moments as the dictator's death and the first democratic elections, is considered the time when social movements tackle the ultimate battle against Franco's regime, preventing its continuity and advocating a break with the dictatorship. The aim of this paper is to outline the process of political change from the perspective of the urban social movements, fixing attention on the struggle that it waged with Francoist local power. The intention is to bring out its major role in the process of delegitimation and disintegration of the Francoist authorities. Similarly, it will pay attention to the discourse and the collective actions and practices that were developed which show a strong aim of rupture with the dictatorship, an urban project and a proposed alternative political articulation of democracy to build that involve the effective participation of citizenship.