The reason for the interest in GCF/serum levels of resistin in periodontitis lies in the fact that epidemiological research indicates that periodontitis interplays between obesity and diabetes mellitus. It is possible that raised levels of resistin in periodontitis can explain at least in part the link between periodontitis and other chronic inflammatory diseases. Therefore, the overall aim of this systematic review was to provide evidence of resistin biomarker in chronic periodontal disease which might underpin the relationship between periodontal disease, diabetes and obesity. Evidence from case-control studies are all summarized and evaluated.