Methodological nationalism is understood as the assumption that the nation/state/society is the natural social and political form of the modern world. We distinguish three modes of methodological nationalism that have characterized mainstream social science, and then show how these have influenced research on migration. We discover parallels between nationalist thinking and the conceptualization of migration in postwar social sciences. In a historical tour d'horizon, we show that this mainstream concept has developed in close interaction with nation-state building processes in the West and the role that immigration and integration policies have played within them. The shift towards a study of 'transnational communities' -the last phase in this process -was more a consequence of an epistemic move away from methodological nationalism than of the appearance of new objects of observation. The article concludes by recommending new concepts for analysis that, on the one hand, are not coloured by methodological nationalism and, on the other hand, go beyond the fluidism of much contemporary social theory.After the first flurry of confusion about the nature and extent of contemporary processes of globalization, social scientists moved beyond rhetorical generalities about the decline of the nation-state and began to examine the ways in which nation-states are currently being reconfigured rather than demolished. That nation-states and nationalism are compatible with globalization was made all too obvious. We witnessed the flouring of nationalism and the restructuring of a whole range of new states in Eastern Europe along national lines in the midst of growing global interconnections. The concomitance of these processes provides us with an intellectual opening to think about the limitations of our conceptual apparatus. It has become easier to understand that it is because we have come to take for granted a world divided into discrete and autonomous nation-states that we see nation-state building and global interconnections as contradictory. The next step is to analyse how the concept of the nation-state has and still does influence past and current thinking in the social sciences, including our thinking about transnational migration.It is our aim in this article to move in this direction by exploring the intellectual potential of two hypotheses. We demonstrate that nation-state building processes have fundamentally shaped the ways immigration has been perceived and received. These perceptions have in turn influenced, though not completely determined, social science