This paper first develops a labor supply forecast for the U.S. labor market in the 1980s, focusing on the effects of the low fertility rates of recent years, and then compares that forecast with the BLS projection of employment demand in the next decade. The author attempts to isolate those occupations and age-sex groups that are likely to have a shortfall of workers and to match the characteristics of those shortage categories with the demographic characteristics of the illegal alien work force. He predicts a relative shortage of unskilled workers in the 1980s, a major departure from past trends, and suggests that an increased flow of immigrants to meet that shortage would benefit skilled older workers and, to a lesser extent, the owners of capital. He also argues, however, that increased immigration would harm domestic unskilled workers—who are increasingly minority group members—by lowering their relative income and raising their equilibrium unemployment rates.