Background : With respect to the relatively high prevalence of nasolacrimal duct obstruction and controversies around the success rate, optimum time of probing, and follow up, the present study was conducted in 6-60 month old children to determine the success rate.

Materials and methods : This clinical trial was performed on 56patients (71 eyes). All patients underwent nasolacrimal duct-probing and irrigation under general anesthesia, then followed for 6 months. Cessation in lacrimation and discharge was considered as a success in probing. Chi-square was used for data analysis.

Results : The overall success rate of probing was 78.6%. There exists an association between child age and success rate (p<0.05). During the first 3 months, 91% had complete improvement.

Conclusion : Success rate of nasolacrimal duct-probing is excellent in patients aged 6-12 months. This success is decreased as age increased. Repeated probing is suggested to be postponed to at least 3-6 months later the first attempts.