In a dynamic model of emigration and return migration I examine the role of migration costs in the process of capital accumulation of the source country. Every migration attempt reduces the amount of savings available for capital accumulation. It contributes, however, to an increase in the per-capita capital stock of the source country if the migrants leave some of their capital behind or decide to return and repatriate accumulated savings. The interaction among these flows governs the evolution of the economy's capital stock and factor rewards, which in turn affects the decisions to emigrate and return migrate. Both the quantitative and qualitative effects of host-country policies and other disturbances on the key macroeconomic variables of the source country are found to depend on the 'level' of migration costs.