IL-6 is an inflammatory mediator that was found with high levels in GCF of chronic periodontitis patients relative to periodontically healthy controls and therefore IL-6 could be considered as marker of chronic inflammation in chronic periodontitis, significant reduction in the elevated levels of IL-6 in GCF was induced 1 and 3 months after non surgical periodontal treatment, significant improvement in clinical parameters as PI, GI, PPD and CAL at study sites was induced by non surgical periodontal treatment. Keywords: IL-6, chronic periodontitis, Gingival crevicular fluid, non surgical treatment, plaque index, gingival index, clinical attachment loss, pocket probing depth