Twenty-one preterm infants (with a mean gestational age and birth weight of 29.3 weeks and 1288.6 g) and nine pretem infants (with a mean gestational age and birth weight of 29.6 weeks and 1153.1 g) were treated with an enteral preparation of indomethacin and with intravenous indomethacin, respectively, for the closure of hemodynamically significant ductus arteriosus. The patients received three doses of either oral indomethacin capsule (Endol, Deva, Turkey) or intravenous indomethacin (Confortid, Dumex GmBH, Germany) in a dose of 0.2 mg/kg at 12-hour intervals. The ductus was closed in 17 (81%) and 7 (77%) of the babies in the orally and intravenously treated groups, respectively (p > 0.05). There was no significant difference in blood urea nitrogen, creatinine levels or thrombocyte counts in either group before and after treatment with indomethacin (p > 0.05). No side effect was reported in the oral indomethacin group. Oral indomethacin may be an alternative to the intravenous preparation in developing countries if the intravenous form is not available or not affordable.