We study the labor market effects of the large immigration wave in Spain between 2001 and 2006. In this period the foreign-born share increased from 6% to 13%, with a total inflow exceeding three million immigrants. Our analysis exploits the large variation in the size of immigration flows across Spain's regions. To identify causal effects, we take advantage of the fact that immigrants' location choices were strongly driven by early migrant settlements that arrived during the 1980s. We find that the relatively unskilled migration inflows did not affect the wages or employment rates of unskilled workers in the receiving regions. The growth of the unskilled labor force was absorbed mostly through increases in total employment. This increase did not originate in changes in the composition of regional output, but was instead driven by changes in skill intensity at the industry level. Regions that received a large inflow of unskilled immigrants increased the intensity of use of the now more abundant (unskilled) labor, relative to other regions. The key industries responsible for this absorption were retail, construction, hotels and restaurants and domestic services. These results are inconsistent with standard open economy models but are in line with recent empirical studies for the United States and Germany.