Background: We investigated whether the "healthy migrant" effect is applicable to an internally mobile U.S.-born population, that is, whether infants born to women that moved within the United States had better birth outcomes compared to those infants whose mothers did not move. Methods: This study used 1995-2001 National Center for Health Statistics live birth/infant death cohort files of singleton infants born in the U.S. to non-Hispanic Black women. Results: Infants born to women who moved had significantly lower risks of low birth weight, preterm birth, and SGA compared to the non-mobile group. Conclusions: There is evidence to support the healthy migrant effect in an internally migrant Black population. The findings of this study suggest infants of non-Hispanic Black mothers who were born in one state and moved prior to delivery had more positive birth outcomes when compared to those infants of women who did not move prior to delivery. © Springer Science+Business Media, LLC 2007.