Among U.S. infants who die within a year of birth, classification of race on birth and death certificates may differ. I investigate two hypotheses: (1) The race of infants of different-race parents is more likely to be differentially classified at birth and death than the race of infants of same-race parents. (2) States with a greater proportion of infant deaths of a given race are less likely to differentially classify infants of that race on birth and death certificates than states with a smaller proportion of infant deaths of that race. Using the Linked Birth/Infant Death data tape for 1983–1985, I assessed the first hypothesis by comparing rates of differential classification for infants with different-race parents and same-race parents. To assess the second hypothesis, I examined the correlations between the proportion of infant deaths of each race in each state and the proportion of infants of that race consistently classified. Differential racial classification on birth and death certificates was more than 31 times as likely with different-race than with same-race parents. The second hypothesis was confirmed for white, black, American Indian, and Japanese infants. As the U.S. population becomes more heterogeneous, attention to these methodologic issues becomes increasingly critical for the measurement and redress of differential racial health status.