Recent work on shifting racial classifications and the fluidity of racial identities in the United States has questioned the subjective and cultural adequacy of dominant racial and ethnic classifications. The cultural legitimacy of biracial, hybrid, and contextual racial identifications appears to be increasing, and the U.S. census now allows Americans to choose multiple races (Brunsma and Rockquemore 2002; Liebler et al. 2017; Rockquemore and Brunsma 2008). According to Brunsma and Rockquemore (2002:112-13), such changes cast "serious doubt on the validity of races as social identities. .. [since] individuals may no longer view themselves in mutually exclusive ways and, at a deeper level, ... others may not view them as members of distinct racial groups." Are traditional racial categories breaking down? This paper examines how Americans racially identify themselves when they are not constrained by traditional fixed-choice categories. We use data from a nationally representative survey panel that included two sets of racial and ethnic identifiers collected at different times: a standard fixed-choice race question that respondents answered when they entered the panel and another asked at the time of 748425S REXXX10.