Striae distensae (SD) or stretch marks are common cutaneous conditions that occur because of the stretching of the dermis.OBJECTIVE To evaluate and compare the efficacy of fractional carbon dioxide (CO 2 ) laser alone versus combined fractional CO 2 laser with platelet-rich plasma (PRP) in SD treatment. Thirty adult female patients with SD (SR and SA) were enrolled. In each patient, a split-lesion design was conducted as follows: pairs of SD on both sides of the midline were selected and allocated to groups A and B. Group A: was treated with combined fractional CO 2 laser with intradermal PRP. Group B: was treated with fractional CO 2 laser alone. Skin biopsies were taken from the lesions before and after treatment for histopathologic evaluation. In group A, a significant excellent improvement of the SD was achieved more than in group B ( p = .007) and the mean of improvement was significantly higher (60.33 ± 26.49) than that in group B (43.80 ± 27.43) ( p -value = .001). Group A was also associated with a more significant dermal deposition of collagen and elastic fibers. Combined fractional CO 2 laser with PRP was more effective than fractional CO 2 laser alone for the treatment of SD.