Forty-two percent of immigrant workers in the United States are women, yet almost all of the evidence on the economic performance of immigrants is based on analyses of men. This study begins to fill the void by examining differences in a wide array of labor market outcomes between U.S.-born and immigrant women, and among immigrant women born in different countries or regions of the world, using the 1970, 1980 and 1990 censuses. Immigrant women were less likely to participate in the labor force, and this gap increased to 7 percentage points by 1990. However, the share of self-employed and the number of weeks and hours worked among employed women were roughly the same for immigrants and natives throughout the 1970-1990 period. The gap in unemployment and weekly wages widened in favor of natives between 1970 and 1990, with a gap in median wages of 14 percent in 1990. However, immigrants born in the United Kingdom and Canada, Europe, Japan, Korea, China, the Philippines, and the Middle East have had steady or improved wages and unemployment relative to U.S.-born women. At the same time, immigrants from Mexico and Central America, who now represent one-quarter of all immigrant women, have experienced relatively high unemployment and low earnings, and these differences have increased, with the wage gap reaching 35 percent in 1990. Disparities in completed years of schooling can explain a substantial share of the differences in labor market outcomes.