This article assesses the labor market implications of less-skilled migration to the United States. It emphasizes how recent social, demographic, and economic trends have reduced the availability of less-skilled native workers, while new low-education immigrant workers compete with other less-skilled immigrants for available low-skilled jobs. Declines in native fertility to substantially below replacement levels, together with native educational upgrading, have substantially reduced the size of the less-skilled native-born labor pool in the past 30 years, even below the level of need. This trend cannot be explained by declines in low-skilled manufacturing employment. Other factors also serve to exacerbate the size of the shortfall in the availability of less-skilled natives, including mismatches in the locations of low-education natives and less-skilled jobs. Nativity differences in health, physical disability, and substance abuse also operate to widen the gap. The resulting void has largely been filled by increasing numbers of less-skilled immigrant workers. These patterns underscore the need for public policies that provide both less-skilled labor and reductions in social and economic inequalities in the United States.