Over a decade, dentistry has become more cognizant of the extent to which behavioural factors such as smoking as well as systemic conditions form a risk-factor for periodontal diseases. Intense studies have been carried out to understand the relationship between respiratory diseases and periodontitis. This can be attributed to the anatomical continuity between lungs and oral cavity, thus making the oral cavity as a site of colonization of respiratory pathogens. Furthermore, the recent increase of tobacco usage has increased the severity of periodontal disease and chronic respiratory disease.Hence this book points out the potential relation between periodontal disease and respiratory disease so that in future, an additional rationale for periodontal therapy may be carried out to prevent untoward effects of oral health on systemic health giving maintenance of oral health the topmost priority for leading an overall healthy and qualitative life.