MMP-13 has been shown to be expressed by periodontitis affected human gingival sulcular epithelium and gingival fibroblasts. Several studies have demonstrated elevated MMP-13 levels in GCF and diseased gingival tissues in chronic periodontitis patients. In addition, increased MMP-13 activity during disease activity has been reported suggesting a role for MMP-13 in periodontal tissue destruction and/or alveolar bone loss.The aim of the present study was assessment of the GCF levels of MMP-13 of chronic periodontitis patients at baseline, 1 and 3 months after non-surgical periodontal treatment versus healthy controls. The study also aimed to test correlations between GCF MMP-13 levels and clinical parameters of chronic periodontitis.The study included 15 patients with chronic periodontitis (5 males and 10 females) with mean age 35 years (range from 30-44 years) and 10 periodontally healthy control subjects with mean age 34 years (range from 28-42 years).In chronic periodontitis patients, gingival crevicular fluid (GCF) samples were collected for assessment of MMP-13 level at baseline, 1 and 3 months after periodontitis treatment from the selected sites presenting CAL ≥ 4mm and evidence of alveolar bone resorption in chronic periodontitis patients.MMP-13 was measured in GCF using enzyme linked immunosorbent assay (ELIZA) technique.The results of the ELIZA revealed a significantly higher level of GCF Pro MMP-13 level in the test group (Chronic periodontitis) versus the control group. Non-surgical periodontal treatment induced significant improvement in clinical parameters as PI, GI, PPD and CAL at selected study sites and at all treated teeth. There was a significant difference in the GCF levels of Pro-MMP-13 between baseline versus 1 month and versus 3 months after non-surgical periodontal treatment.