As Congress debates the fate of more than 10 million unauthorized immigrants living in the United States, their impact on the U.S. low-skilled labor force is an important consideration. In 2005, immigrants overall represented more than a fifth of low-wage workersthose earning less than twice the minimum wageand almost half of workers without a high school education. Unauthorized workers were nearly a tenth of low-wage workers and a quarter of low-skilled workers. The number of low-wage and low-skilled native-born workers fell between 2000 and 2005, due to improvements in their educational attainment but also due to decreasing labor force participation. This report, underwritten by the Hitachi Foundation, describes recent trends in the immigrant labor force and their implications for the U.S. economy.