A case of extremely severe osteolysis secondary to periodontal disease in a 13 years old Yorkshire dog is presented. When referred to our Hospital, the patient had suffered a great loss of dental pieces, severe massive osteolysis in maxilla, mandible and nasal bone leading to oro-nasal fistula and extreme weakening of the affected areas. However, the proprietors had only observed a suppurative wound in the skin. To the authors’ knowledge, the extreme severity of osteolysis affecting both jaws in this dog can not be found in previous scientific descriptions on this species. The treatment consisted of complete teeth removal and general antibiotic medication (Spiramycin/Metronidazole; 10 mg/kg every 24 hours for 10 days, starting 2 days before extraction).  The totally satisfactory evolution of the patient was controlled at days 4^th and 14^th after surgery. Normal alveolar cicatrization was verified. Soft food intake is painless after the teeth removal.

Key words: Dog, Osteolysis, Periodontal disease