The Inter-American Conference on Social Security (CISS) and Universidad Iberoamericana (UIA) co-hosted an international conference on “The Effects of Migration on Sending Countries” in February of 2006. The major objective of the conference was to examine a variety of channels through which migration affects the sending countries. Migrants change the dynamic of sending households; alter labor market supply; and change the skill composition of the labor force in the sending countries. While abroad, they provide family members left behind with a source of income in the form of remittances, a connection to a broader labor market, and a form of insurance against income shocks. Migrants often return with learned experience. A better understanding of the overall effects of migration on sending countries will help policy makers integrate the reality of migrant communities and their impact on society in general to improve policy design. This issue contains five papers originally presented at this Conference.