Periodontitis is one of the most prevalent chronic inflammatory diseases across the globe. The link between periodontitis and rheumatoid arthritis has been well established by various biologically plausible mechanisms in the past decade, however periodontitis being a polymicrobial disease has recently been found to initiate and maintain the auto-inflammatory response that occurs in rheumatoid arthritis.This article focuses on the role of hypercitrullination, as one of the pathologic link between the two forms of chronic diseases.