In the past, most refugees who permanently resettled in the traditional recipient countries of North America, Europe, and Australasia were screened prior to arrival in a host country. In the last decade, increasing numbers of unauthorized refugees or asylum seekers, those who formally lodge application for refugee status in the country in which they are residing, have applied for protection after crossing the borders of these countries. Concerns about uncontrolled migration have encouraged host countries to adopt policies of deterrence in which increasingly restrictive measures are being imposed on persons seeking asylum. These measures include, variously, confinement in detention centers, enforced dispersal within the community, the implementation of more stringent refugee determination procedures, and temporary forms of asylum. In several countries, asylum seekers living in the community face restricted access to work, education, housing, welfare, and, in some situations, to basic health care services. Allegations of abuse, untreated medical and psychiatric illnesses, suicidal behavior, hunger strikes, and outbreaks of violence among asylum seekers in detention centers have been reported. Although systematic research into the mental health of asylum seekers is in its infancy, and methods are limited by sampling difficulties, there is growing evidence that salient postmigration stress facing asylum seekers adds to the effect of previous trauma in creating risk of ongoing posttraumatic stress disorder and other psychiatric symptoms. The medical profession has a role in educating governments and the public about the potential risks of imposing excessively harsh policies of deterrence on the mental health of asylum seekers.