Immigrant female and also male workers are increasingly involved in the supply of care services in the countries of the Global North, and they are especially so in elderly care. In the countries of southern Europe, but to an increasing extent also in countries like Germany and Austria, the care work of immigrants is embedded in a specific care regime. It is undertaken mainly in the recipients' households, often around the clock, and on a live-in basis, so that it supports a system in which the family remains the central locus of care delivery to frail people. Secondly, it employs a large number of workers irregular in regard to the employment relationship, and often also to their legal status. The paper will present the results of various research studies on the topic carried out in Italy within the time-span of a decade (2002–2012). It will discuss how irregular migration is in fact tolerated, when inserted in care work at the service of the growing needs of native families; how the system that I call “invisible welfare” works; and how immigrant care workers find possibilities of agency, despite the constraints of the legal order and the exploitation they often experience at work.