Background: Scarring is a frequent occurrence, since it results from skin damage in individuals of all ages. This work aimed compare clinical results and effect on histopathological architecture and expression of CTGF of the ablative fractional 10,600-nm CO 2 and 2,940 nm Er:YAG lasers in keloid and hypertrophic scars treatment. Methods: that randomized, prospective, double-blinded comparative study included 60 individuals (Fitzpatrick skin type II to V), that are diagnosed clinically and histopathologically with hypertrophic scars. Those were split into 2 groups; 30 patients in group I (Fractional Er:YAG laser), and 30 patients in group II (fractional CO 2 laser). Results: A substantial decrease in post treatment VSS with fractional ablative Er:YAG and Co2 lasers mostly as a result of improved vascularity, pliability and to a lesser extent in height with Er:YAG ,while after CO 2 improvement was significant in height and pliability only. Histopathological examination of skin biopsies in current study, showed that there were increased thickness of epidermis and irregular collagen bands replacement with parallel new collagen fibril organisation after fractional ablative Er:Yag. Immunohistochemical staining of CTGF showed significant reduction 6 months follwoing fractional Erbium YAG and CO2 laser treatment with prominent decrease after Fr Er: YAG. Conclusions: Fractional ablative lasers including both CO2 and Er:YAG have combined impressive ablative laser results with greater protection profile of nonablative lasers. Fractional ablative Er:YAG laser mainly improve vascularity and pliability of hypertrophic scars while Co2 improvement was significant in height and pliability.