Abstract
A one-year-old female mixed breed cat was presented with a prolonged history of the right forelimb lameness. Physical examination revealed pain at the right forelimb by palpation and an open wound was observed at the right armpit, from which the discharge of bloody pus was observed. Radiography of the right forelimb revealed bone lysis and regeneration at the medial proximal humerus, which supported a diagnosis of chronic osteomyelitis. The necrotic, lytic bone and surrounding soft tissue were removed under the general anesthesia. A drainage was attached to the bone defect. After operation, the satisfactory result was obtained by administration of tetracycline based on the antibiotics sensitivity test for about one week.