The authors link the literature on racial fluidity and inequality in the United States and offer new evidence of the reciprocal relationship between the two processes. Using two decades of longitudinal data from a national survey, they demonstrate that not only does an individual’s race change over time, it changes in response to myriad changes in social position, and the patterns are similar for both self-identification and classification by others. These findings suggest that, in the contemporary United States, microlevel racial fluidity serves to reinforce existing disparities by redefining successful or high-status people as white (or not black) and unsuccessful or low-status people as black (or not white). Thus, racial differences are both an input and an output in stratification processes; this relationship has implications for theorizing and measuring race in research, as well as for crafting policies that attempt to address racialized inequality.