The combined effects of maternal and paternal factors on the risk of delivering low birth weight (< 2,500 g) and very low birth weight (< 1,500 g) infants were examined among married parents. Using 1984-1988 natality data compiled by the National Center for Health Statistics, the authors found paternal education and race to have independent effects on the risks of low birth weight and very low birth weight after adjustment for maternal characteristics. The odds of low and very low birth weight decreased with increasing paternal education. Adjustment for paternal education decreased the effect of maternal education on the risks of low and very low birth weight. Additionally, the examination of paternal race led to the identification of a subgroup of married black women with lower risks of low and very low birth weight than married black mothers overall. These data suggest that paternal characteristics should be used' in addition to maternal characteristics, to describe the risks of low and very low birth weight.