Objective: To describe our indications, findings, and outcomes for transcanal endoscopic middle ear exploration in pediatric patients with conductive hearing loss of unknown etiology, without effusions.; Methods: Prospective case series for all pediatric patients undergoing totally endoscopic transcanal middle ear exploration between April 2012 and October 2015 at a pediatric tertiary care referral hospital. Demographic data, operative findings, and hearing results were reviewed.; Results: 21 cases were performed in 20 ears (1 revision). Average age at surgery was 7.98 years and average follow up was 2.1 years. Middle ear pathology identified on CT imaging was confirmed in 55% of cases while identified in 45% of cases where pre-operative imaging was non-diagnostic. 6/20 patients (30%) had an ossicular deformity. 8/20(40%) had bony ossicular fixation. 5/20(25%) had ossicular discontinuity. 2/20(10%) had facial nerve dehiscence impinging on the stapes. 15% had adhesive myringoscierosis or severe granulation causing hearing loss. Prosthetic ossiculoplasty was done in 7/21 (33.3%) of the cases, with 1 TORP, 3 PORP5, and 3 IS joint replacements. Imaging was predictive of intraoperative findings in 13/20 cases (55%). Trainees assisted in 16/21(76%) of cases. The average improvement of PTA was 11.65 dB (range 10 to 36.25), and the average ABG improved 10.19 (range 11.25 to 28.75). There were no perioperative complications or adverse events.; Conclusions: The endoscopic transcanal approach for middle ear exploration offers excellent visualization and is one of the best applications for the endoscopes in pediatric otology cases. This is particularly helpful for "unexplained" conductive hearing loss where ossicular deformity/fixation/discontinuity is suspected. The etiology of the conductive hearing loss was definitively found in 100% of cases, and can be repaired in the same sitting when applicable. (C) 2017 Elsevier B.V. All rights reserved.