Resettlement of refugees and migrants represents a small fraction of the overall world migration. However, this part of a world migration have a legislative basis for the requirement of a migration health screening. Immigrants and refugees and, in some nations, some long-staying visitors such as students, usually need to undergo health assessments as part of their immigration application.

Frequentlly, integrated into the immigration legislation of a given countries, present immigration health policies, rules or regulations are based on two principles:

Protection of Public Health:

Aiming at preventing the introduction of infectious or communicable disease carried by migrants, it focuses particularly on tuberculosis, vaccine preventable diseases, parasitic disease and sexually transmittable diseases.

Reduction of Burden on Publicly Funded Services:

Aiming at reducing the costs or demands for health care or social services that may be required by migrants after arrival, it usually focuses on chronic, high treatment cost health conditions and is most often observed in nations that have state supported national health insurance plans.

Depending on the policies of receiving nations above practices are applied to immigrants but often waived for refugees.

Medical processing of refugees and migrants has been the major activity of IOM Migration Health Department (MHD). It is directly linked with the Organization's mandate to facilitate productive and orderly migration.

Globally, MHD is the largest provider of immigration health assessment and evaluation services, and IOM medical staff have attained a high degree of expertise in this field and provide an exemplary service to clients.