Using the National Longitudinal Study of Adolescent Health (Add Health), we estimate the determinants and direction of change in individual racial identification among multiracial and monoracial adolescents as they transition to young adulthood. We find that while many multiracials subsequently identify as monoracials, sizable numbers of monoracials also subsequently become multiracials. Native American-whites appear to have the least stable identification. We find strong support that socioeconomic status, gender, and physical appearance shape the direction of change for multiracials, and that black biracials are especially compelled to identify as monoracial blacks.