This paper offers a reappraisal of the impact of migration on economic growth for 22 OECD countries between 1986-2006 and relies on a unique data set we compiled that allows us to distinguish net migration of the native - and foreign - born populations by skill level. Specifically, after introducing migration in an augmented Solow-Swan model, we estimate a dynamic panel model using a system of generalized method of moments (SYS-GMM) to address the risk of endogeneity bias in the migration variables. Two important findings emerge from our analysis. First, there exists a positive impact of migrants' human capital on GDP per capita, and second, a permanent increase in migration flows has a positive effect on GDP per worker. Moreover, the growth impact of immigration is high even in countries that have non-selective migration policies.