Background: Hypertrophic scars and keloids may cause cosmetic problem to patients and may also cause pain and pruritus. Different modes of therapy that are currently being used are limited by their efficacy and side effects. Other modes of therapy including laser, are thus being studied for their efficacy. Fractional CO2 laser when used in rejuvenation, increased matrix metalloproteinase 9 (MMP9) level which is undetectable in these scars and so we assumed that the laser could improve these scars by elevation of MMP9 and collagen remodeling. Objective: To examine the clinical efficacy of fractional CO2 laser on these scars and to quantitatively evaluate collagen remodeling (Trichrome stain) and MMP9 through immunohistochemistry. Methods: Thirty patients with either hypertrophic scars or keloids were enrolled in this study. For each patient, the lesion was divided, leaving one half untreated as a control. The other half received 4 laser sessions with 1 and half months apart. Follow up for 6 months was done. Objective clinical assessment was done by a blinded evaluator using Vancouver scar score (VSS). Biopsies were taken before therapy, 1 and 3 months after therapy from the treated areas. Results: VSS showed significant drop in the treated area compared to the untreated area of the scar with significant reduction in itching. There was also significant drop in collagen percentage and significant increase in MMP9 with mostly poor patients’ satisfaction. Conclusion: Fractional CO2 laser is an efficient and safe therapeutic modality for hypertrophic scars and keloids that should be considered as a part of combination therapy for better results.