This study investigates how changing one’s racial classification, specifically, passing as white, affected old-age longevity for African Americans in the pre-Civil Rights era. Using a family fixed-effects model to compare individuals who passed with their siblings who did not, the study finds that passing for white was associated with an average increase of 9.4 months in lifespan. The longevity gains were especially pronounced in the South and among individuals from lower socioeconomic backgrounds. Improved access to education appears to be a key driver. Extrapolating the findings suggests that racial identity had profound and quantifiable consequences for health and survival.