This article is a critical review of racial and ethnic categories on the U.S. Census with a focus on how the census categories affect opportunities to track racial and ethnic inequality. The authors summarize how motivations behind the census categories changed from a historical basis in controlling people of color and protecting Whiteness toward a contemporary orientation around equity. Yet, many issues remain that confound the racial and ethnic census data, which are then used in research. A look at these issues and possible changes for the upcoming 2020 census serves as a critical reminder of the limitations of the census data. Taking this information into account, the authors conclude with comments and suggestions on the principles underlying racial and ethnic data collection on the census and the implications for tracking inequality.