The North is being increasingly confronted with a new phenomenon of migration: the so-called 'health tourism' of irregular migrants. One can already recognize a tendency among would-be migrants who either overstay their visas, or arrive under the pretext of being asylum-seekers, to come to the North with the intention of receiving medical treatment, in particular complicated surgery or other expensive forms of treatment, which they cannot get in their countries of origin, certainly not free of charge. Moreover, many others use 'illness' as a pretext or a reason for not being returned, or to obtain leave of stay. In this respect one needs to take into account that public health services in most Western European and North American countries are already overloaded as a consequence of modern medical developments, but also in view of the general increase in the percentage of old people among the population. Inmany countries there are long waiting lists for non-urgent operations and contributions to health systems have to be constantly increased in order to cover the extensive costs of modern medical treatment.