Aims: To evaluate the long-term surgical success of transcanalicular dacryocystorhinostomy (TCDCR) with diode-laser in the treatment of epiphora due to isolated naive nasolacrimal duct obstruction (NLDO) in adults. Methods: This retrospective study included patients with isolated naive NLDO, who underwent diode laser-assisted TCDCR. No patients had pathology in the nasal region detected by an otorhinolaryngologist. The included patients had documented information about epiphora evaluation with lacrimal system irrigation with fluorescein dye, and annual direct imaging of osteotomy patency with nasal endoscopy. Success was defined as no postoperative epiphora, conjunctivitis or dacryocystitis, an open passage in the lacrimal system lavage, and patient satisfaction. Results: The study included 116 patients [mean age: 49.6±11.4 years, female: 67 (57.8%)]. The success rate was 84.5% in the first year, 80.2% in the second year, and 76.7% in the third year. Following the operation, 9 (7.8%) patients had epiphora, 8 (6.9%) patients were not satisfied, and 1 (0.8%) patient developed conjunctivitis/dacryocystitis in the first year. Three (2.6%) patients had dissatisfaction and 2 (1.7%) patients had the complaints of epiphora correlated with nasolacrimal lavage obstruction in the second year. Two (1.7%) patients were dissatisfied and 2 (1.7%) patients had epiphora complaints confirmed with nasolacrimal lavage in the third year. Conclusions: The present study showed that the treatment of epiphora due to isolated NLDO with diode laser-assisted TCDCR can provide long-term success in major outcomes in adult patients. [ABSTRACT FROM AUTHOR]