OBJECTIVE: The aim of the study was to determine the effects of antenatal maternal corticosteroid treatment on selected neonatal outcomes in infants weighing ≤1000 g at birth after preterm rupture of membranes. STUDY DESIGN: In a 1-year (1992-1993) prospective observational study, the National Institute of Child Health and Human Development Maternal-Fetal Medicine Units Network collected outcome data for 766 infants who did not have a major fetal anomaly and who had a birth weight ≤1000 g (378 were born after preterm rupture of membranes). Only fetuses deemed potentially viable by the obstetrician were included in our analysis. Selected neonatal outcomes were compared between mothers who did and did not receive antenatal corticosteroids. Logistic regression variables included birth weight, sex, race, amnionitis, tocolytic therapies, mode of delivery, and surfactant use. RESULTS: Two hundred fourteen of the 378 infants whose mothers had preterm rupture of membranes were deemed potentially viable; 62 of these mothers received antenatal steroids and 152 did not. Groups were similar with respect to gestational age, birth weight, race, amnionitis, and delivery mode. Women who received antenatal steroids were more likely to have received tocolysis (P < .001). Univariate and regression analyses controlling for multiple confounders confirmed no neonatal benefits of maternal corticosteroid use. CONCLUSIONS: Corticosteroid treatment in women with preterm rupture of membranes was of no apparent benefit to neonates weighing <1000 g.