Purpose: to describe clinical characteristics of nasolacrimal duct obstruction and to assess the efficacy of endonasal dacryocystorhinostomy with silicon intubation. Methods: A prospective series cases noncontrolled study, 34 eyes of 31 patients included in study had nasolacrimal duct obstruction and had not had previous lacrimal surgery. Patients had endonasal dacryocystorhinostomy with silicon intubation between December 2006 and May 2009 at the Vietnam-Cuba hospital, Dong Hoi Frienship Hospital. Results: 34 eyes of 31 patients were performed (16 males, 15 females). Mean age of the patients was 41.23 + or - 7.1 years old. Common symptoms were epiphora (100 percent) and/or mucocele (70.59 percent). Signs: lacrimal irrigation of all case had reflux water from opposite punctum, 70.59 percent eyes had reflux mucus when pressure over the lacrimal sac. The cause of nasolacrimal duct obstruction 70.59 percent eyes was chronic dacryocystitis, 23 percent sinus-nouse 5.9 percent trauma. Mean follow up time was 8 months, the surgical susccess rate was 92.20 percent. Conclusion: Nasolacrimal duct obstruction has multiform clinical characteristics. Endonasal dacryocystorhinostomy is safe technique, so Ophthalmologists and ENT physicans should be cooperated closely to offer more benefits to patients.