This article provides an empirical test of the widely accepted assumption that migration contributes to union instability. The data come from the Mexican Migration Project (MMP) data base MMP93. We use multilevel discrete time event history analysis to specify the odds of union dissolution for male household heads by individual- and community-level U.S. migration experience. In the context of the U.S.-Mexico migration flow, we find that U.S. migration significantly increases the odds of union dissolution for individuals with extensive migration experience as well as for residents in communities with medium international migration levels. We conclude that changes in normative values and social control levels, for both individuals and communities, are partial contributors to this relationship.