Forty-six infants exposed to indomethacin in utero for treatment for preterm labor were compared with infants from two control groups. In one control group the next consecutive patient treated with a tocolytic agent was used, and the other control group was formed by picking the next consecutive patient matched by gestational age who did not receive any tocolytic agent. There was no significant difference in Apgar scores, birth weight, or gestational age in the three groups. The incidence of neonatal complications including hypocalcemia, hypoglycemia, respiratory distress syndrome, patient ductus arteriosus, sepsis, and neonatal mortality were not significantly different in the three groups. No cases of premature closure of the ductus arteriosus or persistent fetal circulation were seen.