Abstract: Periodontal disease is an inflammation of periodontal tissues that include gingiva, cementum, alveolar bone and periodontal ligament. They occur mostly in dogs and cats mainly due to a lack of oral hygiene. Therefore, care must be taken to minimize occurrence of these problems. Since periodontal diseases can occur as a complex in 4 stages, clinical symptoms should be carefully evaluated for effective treatment. This review study provides extensive information on etiology, epidemiology, treatment and prognosis of periodontal diseases in pet animals.