This study compares maternal and infant health and sociodemographic characteristics of U.S.-born and foreign- or Puerto Rican-born Hispanic mothers and their babies, using data from the national vital statistics system and the 1980 National Natality Survey. While nearly half of all Hispanic mothers and Mexican and Puerto Rican mothers were born in the United States, less than 10 percent of Cuban and other Hispanic mothers were U.S. born. Compared with foreign- or Puerto Rican-born Hispanic mothers, U.S.-born mothers tended to be younger, to have had fewer high-order births, to be less likely to receive delayed or no prenatal care, to have higher educational attainment, and to be more likely to be unmarried. The incidence of low birth weight among infants born to Hispanic mothers, particularly Mexican and Cuban women, was relatively low. When the proportions of low birth weight were examined by nativity status, infants born to foreign- or Puerto Rican-born women were consistently less likely to be of low birth weight. In an effort to account for these findings, the mother's smoking status before and during pregnancy is examined. Compared with non-Hispanic mothers, Hispanic mothers were much less likely to have smoked before or during pregnancy. These data are examined to see if they account for the better outcome as measured by birth weight for Hispanic births, especially those to foreign- or Puerto Rican-born women.