This article examines in a comparative perspective the regulations to contain the process of family reunification implemented by the French and British governments in the early 1970s. The comparative analysis highlights how, despite their stemming from different legal systems, these rules repeatedly attempted to deny any right to family reunification, and shows that social and legal definitions aimed at measuring the extent of the family became more than once a source of many difficulties in the admission process. The comparison also allows for an evaluation of the way these controls were administered at points of departure and ports of entry and, more significantly, examines the predominance of governmental and administrative structures to demonstrate how in both cases these rules led to numerous infringements of immigrants' fundamental rights.