The literature on development in economics and sociology has tended to focus on capital flows, investments, and, more recently, institutions as key causal factors. International migration, when discussed, is relegated to the status of a symptom of underdevelopment and even a factor contributing to it. The more recent literature on migrant remittances has partially reversed this view by documenting large hard currency transfers made by expatriates to their home countries. This changed approach to migration and development does not go far enough because it does not take into account the organized efforts of immigrant communities themselves. Nor does it consider important developmental synergies produced by the rising interactions between immigrant organizations and sending-country governments. Using data from a recently completed comparative study, we document these processes for two major countries of out-migration—Mexico and China. The study compiled inventories of migrant organizations from both countries in the United States, interviewed leaders of the major ones, and complemented these data with interviews with officials and community leaders in each sending country. Profiles of these transnational ties were constructed, exemplifying their increasing density and developmental impact at the local and national levels. Theoretical and policy implications of the findings are discussed.