The term "migrant worker" has different official meanings and connotations in different parts of the world. The United Nations' definition is broad, many people were working outside of their home country. Some of these are called expatriates. Several countries have millions of foreign workers. Some have millions of illegal immigrants, most of them being workers also.
According to the International Labour Organization, as of 2014 there were an estimated 232 million international migrants in the world (defined as persons outside their country of origin for 12 months or more) and approximately half of them were estimated to be economically active (i.e. being employed or seeking employment).
According to the Panos Network, it is never appropriate to refer to asylum-seekers or refugees as “illegal migrants”. On the one hand, their reasons for moving are different from those of migrants, and on the other, international law recognizes that those fleeing conflict or persecution may need to cross international borders without authorization and should not be penalized for doing so. The term can also be used to describe someone who migrates with in a country, possibly their own, in order to pursue work such as seasonal work.
The "United Nations Convention on the Protection of the Rights of All Migrant Workers and Members of Their Families" defines migrant worker as follows:
The Convention has been ratified by Mexico, Brazil, and the Philippines (amongst many other nations that supply foreign labour) but it has not been ratified by the United States, Germany, and Japan (amongst other nations that receive foreign labor).
Since the 1960s, farmers in Ontario and other provinces have been meeting some of their seasonal labour needs by hiring temporary workers from Caribbean countries and, since 1974, from Mexico under the Canadian Seasonal Agricultural Workers Program (CSAWP). This federal initiative allows for the organized entry into Canada of low- to mid-level skilled farm workers for up to eight months a year to fill labour shortages on Canadian farms during peak periods of planting, cultivating and harvesting of specified farm commodities. The program is run jointly with the governments of Mexico and the participating Caribbean states, which recruit the workers and appoint representatives in Canada to assist in the program's operations.