Shaar Haaliya--Israel's Ellis Island during the mass immigration of the 1950s--is a case study that challenges the historian's understanding of the concept of quarantine. It was isolated and fenced off for declared health purposes and was widely referred to as a quarantine, but archival and historiographical documentation suggest that Israeli public health policy did not define it as such. I track the discussion and conflict surrounding Shaar Haaliya's function and perception as a quarantine. This is a story that illuminates the way fear of disease converged with fear of immigration as well as the way defiance of public health institutions took shape in a unique framework of citizenship and during a unique wave of migration.