This dissertation examines the determinants of internal and international migration from rural areas of Mexico. The research analyzes a national representative survey of more than 400 rural Mexican communities and an Ethnosurvey of two communities located in Western Mexico, the main source of international migrants. A contextual model incorporating variables at the individual, household, and community levels is implemented. Internal migration from rural areas of Mexico is still more prevalent that international moves. Network connections, the webs that link potential migrants in sending communities to people in receiving society, are the most important determinant of both internal and, especially, international migration. Maturation of networks brings an institutionalization of the migration process. Once high levels of migration to the United States from a community are established other factors become less important in determining migration. Factors operating at the household level tend to be more important when migration to the United States is relatively low than when it is high. Household dependency is a significant predictor of internal but not of international migration.