To compare the success rate of monocanalicular versus pushed monocanalicular silicone intubation (PMCI) of the nasolacrimal duct for congenital nasolacrimal duct obstruction (CNLDO).In a prospective randomized clinical trial 53 eyes of 49 patients with CNLDO underwent either monocanalicular silicone intubation (MCI) (n=28 eyes) or PMCI (n=25 eyes). All procedures were performed by 1 oculoplastic surgeon. Treatment success was defined as the complete resolution of epiphora at 3mo after tube removal.The surgical outcome was assessed in 20 eyes with MCI and 20 eyes with PMCI. The mean age of treatment was 26.25±10.08mo (range, 13-49mo) for MCI and 26.85±12.25mo (range, 16-68mo) for PMCI. Treatment success was achieved in 18 of 20 eyes (90.0%) in the MCI group compared with 10 of 20 eyes (50%) in the PMCI group (P=0.01). In the PMCI group, the tube loss (30%) was greater than the MCI group (5%), however the differences between the 2 groups proved to be not significant (P=0.91).Our results indicate that MCI has higher success rate in CNLDO treatment compared with PMCI in this small series of patients.