Roughly one third of migrants worldwide reside in developing countries, yet most papers on the macroeconomic effects of immigration focus on advanced economies. We investigate the medium-and long-term effects of immigration in an emerging country, considering a salient feature of this type of economies: the importance of labor informality. We build an overlapping generations model featuring 24 cohorts, an informal sector, and households with heterogeneous skill levels, among other features, that help us match key demographic and economic characteristics of Chile, an emerging country that has recently experienced an important immigration wave. An immigration wave increases the supply of labor, creating downward pressure on wages in the formal sector. Workers respond by reallocating labor effort to the informal sector, which allows them to mitigate the decline in consumption per worker triggered by lower formal-sector wages. Our model, thus, constitutes a framework for the quantitative analysis of immigration in emerging countries. Resumen Alrededor de una tercera parte de los migrantes del mundo reside en países en desarrollo. Sin embargo, la mayoría de investigaciones sobre los efectos macroeconómicos de la inmigración se enfocan en países avanzados. En este artículo investigamos los efectos de mediano y larzo plazo de la inmigración en un país emergente, considerando una característica clave de este tipo de economías, la importancia del trabajo informal. Para esto, construimos un modelo de generaciones traslapadas con 24 cohortes,  We thank Matías Tapia, Benjamín García, and participants the CEF conference in Ottawa and the SECHI conference in Santiago for useful comments. We also thank Elías Albagli for encouraging us to work on this project, and several colleagues for sharing data, results,