How do the efforts at social protection by cross-border migrants impact upon social inequalities? While the 'old' social question between workers and capitalists was addressed within the frames of national welfare states and social policies from the late nineteenth century onwards, the 'new' social question - running along diverse lines of inequalities, such as gender, class, ethnicity and religion - has implications far beyond national borders since flows of persons, goods, capital and services are transnational. Migrations are of particular relevance for understanding the transnational social question because they link the disparate and fragmented worlds of unequal life chances and social protection. Of particular interest is the question of how cross-border social protection involving migrants results in the reinforcement of existing inequalities, e.g. between regions and within households, and creates new lines of inequalities. This state of affairs necessitates a rethinking of national social citizenship and its significance for the legitimation of social inequalities.