Periodontitis is a group of inflammatory diseases that affect the connective tissue attachment and supporting bone around the teeth whose initiation and progression depends on the presence of virulent microorganisms capable of causing disease. Periodontitis is considered to be a multi factorial disease with no clear cut etiology, so its identification and early diagnosis becomes more difficult.The current clinical diagnostic parameters were introduced more than 50 years ago. But all the methods provide disease severity rather than disease activity. A biomarker is a substance used to indicate a biologic state and is an objective measure to evaluate the present and future disease activity. It is defined as ¿ A substance that is measured objectively and evaluated as an indicator of normal biologic processes, pathogenic processes, or pharmacologic responses to a therapeutic intervention.Various biological media like saliva, serum and GCF are used to determine biomarkers in periodontal health and disease. This book provides all information about Biomarkers in Periodontal disease and about clinical relevance for determination of Periodntal disease.