This retrospective study demonstrates the role of dacryoendoscopy to identify causes of failed lacrimal probing in congenital nasolacrimal duct obstruction (CNLDO). Dacryoendoscopy was carried out in 13 children with refractory CNLDO. The lacrimal pathway was examined from puncta to the valve of Hasner under general anaesthetic using 0.8mm Erlangen miniature straight forward zero degree semiflexible endoscope. It has a fibreoptic light source, side port for irrigation and a high definition camera unit. The dacryoendoscopy was carried out from upper punctum and canaliculus and passed through the lacrimal sac and nasolacrimal duct. Simultaneous visualisation of the inferior meatus with 2.7mm nasal endoscope helped with differentiating a proximal block from a distal block of the nasolacrimal duct. Out of 13 cases, four had dysgenesis of bony nasolacrimal duct, four cases had dacryolith, three cases had an intact membrane at the lower end of nasolacrimal duct and two cases had fibrosis of the lower end of nasolacrimal duct and the surrounding area in the inferior meatus following previous interventions. Dacryoendoscopic recanalisation was done in seven cases whilst six cases needed endoscopic dacryocystorhinostomy. At six months all children were asymptomatic. The authors conclude that dacryoendoscopy facilitates direct examination of the nasolacrimal system and has an added advantage over nasal endoscopy assisted probing in refractory cases of CNLDO.