Aim: this study preformed to evaluate clinically and radiographically, the efficacy of Metformin Gel in the surgical treatment of intrabony periodontal defects. Subjects and methods: Twenty chronic periodontitis patients with intrabony defect were divided randomly into two groups. Group I: ten patients with infrabony defects treated by open flap surgery only. Group II: ten patients with infrabony defects treated by open flap surgery combined with metformin gel 1%. Clinical and radiographic parameters were gathered at baseline, 6 and 9 months. Results: There were statistically significant differences between Group I & Group II at 6 months regarding probing depth, clinical attachment level and marginal bone level. And vice versa, no statistically significant differences at 9 months. Conclusions: usage of metformin gel 1% seems to be superior in gaining bone than surgical treatment by open flap surgery only but this improvement was limited in time, that was probably due to gel formulation or lower concentration of metformin.