The worldwide phenomenon of intercountry migration will be one of the defining features of the 21st century, as it was for the last third of the 20th century. According to a report by the United Nations, there are an estimated 214 million international migrants in the world today. The United States, the largest immigrant-receiving country, had 38 million foreign-born people (13% of its total population) in 2008, a nearly quadruple increase from 1970 when there were only 9.6 million immigrants [Page 641](4.7%). This entry discusses the intricate links between international migration and immigrant health, focusing on the health status and use of health care by immigrant family members.