Respiratory diseases are responsible for a significant number of deaths and considerable suffering in humans. Accumulating evidence suggests that oral disorders, particularly periodontal disease, may influence the course of respiratory infections like bacterial pneumonia and chronic obstructive pulmonary disease (COPD). Oral periodontopathic bacteria can be aspirated into the lung causing aspiration pneumonia. The teeth may also serve as a reservoir for respiratory pathogen colonization and subsequent nosocomial pneumonia. The overreaction of the inflammatory process that leads to the destruction of the connective tissue is present in both periodontal disease and emphysema. This overreaction may explain the association between periodontal disease and chronic obstructive pulmonary disease. The mechanisms of infection could be the aspiration into the lung of oral pathogens capable of causing pneumonia, colonization of dental plaque by respiratory pathogens followed by aspiration, or facilitation of colonization of the upper airway by pulmonary pathogens by periodontal pathogens. The present article briefly reviews the epidemiologic evidence & role of periodontopathogens in causing respiratory infections.