Melatonin is a hormone that is secreted from the pineal gland in cases where there is no light and is effective in regulating many biological functions such as sleep, circadian rhythm, immunity and reproduction. Melatonin has a free radical scavenger, immunity-supporting and antioxidant effect. Periodontal disease is a common chronic inflammatory disease. This disease has stages ranging from gingivitis to periodontitis. Supportive tissue destruction due to periodontal disease causes tooth loss. Previously, the existence of an inverse relationship between the amount of antioxidants and LPO products has been demonstrated in periodontal disease. PMNL infiltration plays an important role in periodontal disease. These cells produce large amounts of ROS that cause tissue damage. Determination of oxidative stress parameters and melatonin in the individuals with periodontal disease may provide important information on susceptibility to this disease, prognosis and treatment.