There is abundant research on how social cleavages shape political preferences in developed countries with uninterrupted democracies, but we know less about this topic for middle income countries with recently restored democracies. In this analysis of the Chilean case, we examine with Latinobarometer survey data from 1995 to 2009 the evolution of social cleavages as shapers of political preferences (measured with a left-right self-placement scale). We find a general process of dealignment across time, indicated by the decreasing association between political preferences on the one hand, and class, religion and regime preferences on the other. We tentatively link dealignment at the mass level to the strategies pursued by political parties operating in a political and economic context that encourages ideological moderation and convergence to the centre. These strategies weaken the differentiated signals needed for sustaining an aligned citizenry.