Purpose: Endoscopic dacryocystorhinostomy (en-DCR) is the mainstay of treatment of patients with nasolacrimal duct obstruction, with current success rates above 90%. Our aim was to evaluate multiple demographic and technical factors and estimate its influence on the outcome of en-DCR. Methods:We performed a retrospective review of the clinical records of patients submitted to a DCR at the Lacrimal Surgery Unit of the Centro Hospitalar Tondela-Viseu between June 2010 and December 2018, and collected data on demographic characteristics, preoperative consultation notes, surgical reports, complications and follow-up results.Results: Our study included 107 en-DCR procedures (92 consecutive patients), with an overall success rate of 89.7%. The post-operative finding of granulation tissue by post-operative week 6 was associated with a negative outcome (p = 0.001). None of the other variables studied achieved a statistically significant association with the outcome, including the presence of multiple comorbidities, performance of ancillary procedures or history of dacryocystitis; however, previous ocular surgery showed a tendency toward poorer results. Conclusion:Determining factors associated with surgical failure can help advice patients accordingly in the preoperative setting. Our study analyzed multiple variables and concluded that previous ocular surgery approached a statistically significant association with the outcome. The addition of ancillary procedures (nasal or ophthalmological) does not negatively influence the outcome of en-DCR and the presence of comorbidities should not preclude surgery.