Abstract Background This prospective clinical study evaluates the effect of a silicone stent tube (SST) on the success rate of endonasal-endoscopic dacryocystorhinostomy (EN-DCR) to treat primary acquired nasolacrimal duct obstruction. Methods Patients were randomly assigned to receive EN-DCR with or without SST intubation over a period of 3 months. The surgery was performed using standardized techniques. Patients were assessed at three different timepoints: one day, 12 weeks and 24 weeks after the surgery. The results were compared in order to evaluate statistical differences. Surgical success was determined by means of positive irrigation procedures, as well as by the improvement of symptoms and a high level of patient satisfaction. Results A total of 56 randomized cases completed 24 weeks of follow up. 1 Patient dropped out due to malignant genesis of the nasolacrimal duct obstruction. After 24 weeks of follow up no statistically significant differences in levels of epiphora (p > .10) or patency (p > .16) were revealed. Comparisons regarding changes in time did not show levels of significance (p > .28). Conclusions This study could not confirm a statistically significant benefit or disadvantage for SST Insertion in EN-DCR.