A 2 year old Welsh pony cross gelding presented to the Cornell University Equine and Farm Animal Soft Tissue Surgery Service with facial swelling and a draining tract on the ventral surface of his left mandible. On presentation, the patient was bright, alert and responsive and physical examination revealed purulent, malodorous discharge from the draining tract on his left ventral mandible as well as an enlarged left mandibular lymph node. Mandibular radiographs revealed lytic alveolar bone surrounding the apex of tooth 309 and a gas filled draining tract in the rostroventral soft tissues. A large periodontal pocket in the gingival sulcus of tooth 309 was discovered on oral examination. The pony was diagnosed with a periapical infection of tooth 309 and the tooth was surgically removed under general anesthesia using a lateral buccotomy technique. The patient recovered well from the procedure and was given an excellent prognosis for long term dental health.