A 25-year-old Thoroughbred gelding presented to Cornell University’s Equine and Farm Animal Hospital (EFAH) in September 2008 for weight loss and trouble masticating. Oral examination revealed severe incisor pain and signs of periodontal disease. Intra-oral radiographs revealed resorption, hypercementosis, and periodontitis. All maxillary incisors and teeth 302 and 303 were extracted under standing sedation with regional and local anesthesia. The patient presented again in June 2012 with pain in his remaining incisors. Oral examination and radiographic findings revealed disease progression and the remaining incisors were extracted. This horse was diagnosed with Equine Odontoclastic Tooth Resorption and Hypercementosis (EOTRH), a painful disease of the incisors and canines of older horses that has been identified worldwide within the last decade. The pathogenesis of EOTRH remains unclear and may be multifactorial. This paper will discuss clinical signs, diagnosis, and treatment of EOTRH.