Periodontal diseases are among the most common human infections that not only impact oral health but also are associated with adverse systemic diseases such as cardiovascular diseases, stroke, diabetes, and respiratory diseases. Periodontal diseases is a chronic severe inflammatory process of the gingiva leading to the destruction of tooth-supporting structures, alveolar bone, and subsequently tooth loss due to bacteria infection. While it has been reported that several oral biofilm-forming bacteria might be involved, the role of C. pneumoniae infection in the pathogenesis of periodontal disease remains unknown. The present hypothesis proposes that C. pneumoniae is involved in the pathogenesis of periodontal diseases. This will lead to a better understanding of the etiopathogenesis of periodontal disease, better treatment strategy and savings on total health care costs.