The authors investigated the efficacy of antibiotic irrigation as the therapeutic option in congenital nasolacrimal duct obstruction. We retrospectively reviewed the medical record of 76 patients' eyes in whom congenital nasolacrimal duct obstruction had been diagnosed. In 50 of these patients, the colonizing microorganism was identified and, irrigation through canaliculi was performed using antibiotics of suitable sensitivity. Nasolacrimal system probing was performed on 26 patients as the control group. Treatment was regarded successful when over a 4 week period epiphora or mucous discharge disappeared and when saline passed without resistance on irrigation. 96.0% of patients in the irrigation group and 84.6% of patients in probing group were treated successfully. There was no statistical difference in the success rate between the two groups (P=0.173). The recovery period based on culture results was 3.22±0.37 months in the group in which microorganisms were isolated and 2.39±0.35 months in the group in which no organisms were isolated. There were no statistically significant differences in the success rates between the group in which there was growth and the group in which there was no growth (P=0.1308). Thus a similar result was obtained using nasolacrimal probing and canaliculus antibiotic irrigation in congenital nasolacrimal duct obstruction. Antibiotic irrigation is a safe and simple therapeutic option in congenital nasolacrimal duct obstruction.