Purpose: To evaluate success rate of initial probing for congenital nasolacrimal duct obstruction and influencing factors in children less than 5 years.Materials and methods: From November 1998 to June 2000, 207 eyes from 161 patients underwent nasolacrimal duct probing and irrigation.Results: Overall success rate was 83.9% varing from 50 to 100%, depending on the age of the patient, type of the nasolacrimal obstruction, and canaliculus status.Conclusion: Success rate of initial probing is excellent in patients less than one year, whilst it is fare in patients between 1-5 years old.