The U.S. job structure became increasingly polarized at the turn of the twenty-first century as high- and low-wage jobs grew strongly and many middle-wage jobs declined. Prior research on the sources of uneven job growth that focuses on technological change and weakening labor market institutions struggles to explain crucial features of job polarization, especially the growth of low-wage jobs and gender and racial differences in job growth. I argue that theories of the rise of care work in the U.S. economy explain key dynamics of job polarization—including robust growth at the bottom of the labor market and gender and racial differences in job growth—better than the alternative theories. By seeing care work as a distinctive form of labor, care work theories highlight different dimensions of economic restructuring than are emphasized in prior research on job polarization. I show that care work jobs contributed significantly and increasingly to job polarization from 1983 to 2007, growing at the top and bottom of the job structure but not at all in the middle. I close by considering whether the care economy will continue to reinforce job polarization, or whether it will provide new opportunities for revived growth in middle-wage jobs.