Drawing on interview data with black-white biracial adults, we examine the considerable agency most have in asserting their racial identities to others. Extending research on "identity work" (Snow and Anderson 1987), we explore the strategies biracial people use to conceal (i.e., pass), cover, and/or accent aspects of their racial ancestries, and the individual and structural-level factors that limit the accessibility and/or effectiveness of some strategies. We further find that how these biracial respondents identify is often contextual--most identify as biracial, but in some contexts, they pass as monoracial. Scholars argue that passing may be a relic of the past, yet we find that passing still occurs today. Most notably, we find a striking reverse pattern of passing today--while passing during the Jim Crow era involved passing as white, these respondents more often report passing as black today. Motivations for identity work are explored, with an emphasis on passing as black. (Contains 3 footnotes.)