PURPOSE The purpose of this study was to evaluate the results of a teamwork revision endoscopic dacryocystorhinostomy (DCR) in eyes with previously failed external DCR. METHODS This retrospective study was performed on 50 failed external DCR subjects who underwent a teamwork revision endoscopic DCR by an ophthalmologist and an otolaryngologist. Paranasal sinus CT scanning was performed for each patient before the revision surgery. During surgery, any abnormal tissue noticed before silicone intubation was sent for pathological evaluation. RESULTS Endoscopic revision DCR was performed on 50 failed external DCR subjects with one-year follow-up. Of these, 31 were female (62%). The age range of the subjects was 18-88 years (mean: 59.98 years). Sinus CT showed at least one abnormality in 94% of cases. Revision endoscopy showed septal deviation (66%), scar formation (32%), ostium problems (28%), and sump syndrome (6%). Pathologic and clinical findings showed that chronic inflammation had a significant association with scar tissue and septal synechia (P = 0.001 and 0.008, respectively). At the final follow-up, anatomical and functional success was achieved in 45 out of 50 (90%) of subjects. CONCLUSION Endoscopic revision DCR when performed as cooperation of otolaryngologists and ophthalmologists may help resolve the endonasal problems and increase the success rate.