Periodontal disease is an immune-inflammatory response of tooth supporting structures. It's onset depends upon various factors like poor oral hygiene, smoking, systemic diseases such as diabetes mellitus, cardiovascular diseases and also psychological factors which act together to create favorable conditions for the development and progression of the disease. As we know, effects of psychological and emotional condition on the individual's immune response predispose the emergence of several pathologies and also, psychological factors like depression affect a large section of the modern population.It is necessary to assess the role of depression in pathogenesis of periodontal disease. This book will help in increasing knowledge about the relationship between depression and periodontal disease.