Objective: The purpose of this systematic review (SR) was to answer the focused research question: Is there an association between periodontal disease and pneumonia or chronic obstructive pulmonary disease (COPD)? Method: Databases and keywords searched included: Medline, best viagra PubMed, and the Cochrane Database of Systematic Reviews on combinations of lung disease, obstructive pneumonia, and periodontal disease. The literature searches were limited to 1997 to 2011; humans; and in English. Inclusion criteria were RCTs/clinical trials, SRs/meta analysis, and longitudinal, cohort, case control, multicenter and epidemiological studies for links between COPD or pneumonia and periodontal disease. Results and Discussion: 114 articles from databases, and 22 from hand searching were scrutinized for predetermined inclusion and exclusion criteria. Of these, 17 and 4 (n=21) respectively met the criteria, were analyzed and scored independently by each reviewer to extract evidence: 1) seven well designed studies and 3 systematic reviews provided fair evidence of an association between periodontal disease and pneumonia; 2) two small scale studies, at lower levels of quality of evidence, indicated conflicting results; 3) five well designed longitudinal or matched case control studies provided fair evidence of an association between periodontal disease and COPD; 4) four large scale, retrospective studies also supported this association. Conclusion: A causal association between respiratory diseases (pneumonia or COPD) and periodontal diseases remains conjectural. The conclusions reached based on this SR indicate there is fair evidence Grade–B, Level II-2–supporting: 1) an association of pneumonia and periodontal disease concurring with previous reviews; 2) an association between COPD and periodontal disease.