The current clinical study was conducted in an attempt to demonstrate the effect of ozone on the healing process after surgical removal of mandibular third molar. Twenty healthy patients subjected to removal of bilaterally impacted third molar nearly the same classification and surgical difficulty evaluated by Pederson and parant scale. Ozone generator device used to deliver ozone before and after the surgery only to left side (study group) and compared to the right side which not subjected to ozone (control group). The healing, pain, edema and bacterial count studied and analyzed clinically, microbiologically and radiographically. The results of this study revealed Significant increase in wound healing after surgery and bone density after 3 months in the side of ozone therapy , Significant decrease in pain severity and percentage of facial edema in the ozone group after surgery and significant antibacterial effect .