Purpose: To determine the risk factors impacting the surgical success of primary monocanalicular stent intubation for congenital nasolacrimal duct obstruction (CNLDO). Methods: This is a retrospective interventional case series of patients 18 years and younger treated more than a 12-year period with monocanalicular stent intubation with inferior turbinate fracture for CNLDO by a single surgeon. Patients with dacryocystoceles, dacryocystitis, Down syndrome and previous tear duct surgery were excluded. An intraoperative grading scale of tear duct stenosis, date of stent removal, stent length, and postoperative symptoms were recorded. Surgical success was defined as the complete resolution of symptoms. Results: One thousand four hundred sixty-nine stents were placed in 1,001 pediatric participants (533 unilateral, 468 bilateral). The mean age at surgery was 1.86 years (0.1-18.07). The mean follow up was 34.99 months (0.43-134.3) with mean in-office stent removal at 3.41 months (0.63-36.9). Early stent loss occurred in 14.8% intubations (217/1,469). The overall success rate was 92.4% (1,357/1,469 eyes). Subjects less than the age of 4 years had a success rate of 92.8% (1,296/1,397) compared with 84.7% (61/72) in children more than 4. In multivariable analysis, bilateral surgery, severe tear duct stenosis, and early stent loss were significantly associated with higher risk of surgical failure. Conclusions: Severe tear duct stenosis, early stent loss, and bilateral surgery were significant risk factors for surgical failure. While the success rate stratified by age at surgery suggested a lower success after the age of 4. Primary monocanalicular stent intubation is an effective and safe treatment for CNLDO sparing a child the need for multiple staged surgeries.