Scarring occurs during the healing of active acne and can be caused by all types of acne. Acne scars impair quality of life and have been described as a risk factor for suicide, depression, low academic performance, and unemployment. In this study, we aimed at evaluating the efficiency and safety of fractional carbon dioxide laser in the treatment of atrophic post acne scars. This study was carried out in Benha University and Kobbery El-Kobba Dermatology, Venereology & Andrology Departments and included 20 patients having moderate to severe facial post acne scars. All patients were Fitzpatrick skin types III- V. Four treatment sessions with 4-week intervals were done for all patients. Twenty subjects [100%] completed four treatment sessions. The clinical types of acne scars were determined prior to treatment and classified according to the predominant type into Boxcar scars in six patients [30%], ice pick scars in 10 patients [50%] and rolling scars in four patients [20%]. Acne scars showed great improvement after treatment. 30% and 50% of patients were highly satisfied and satisfied respectively after the end of treatment. Facial erythema, as an adverse effect was evaluated one week after each session through applying Clinician Erythema Assessment scale [CEA]. The erythema was cleared of three [15%]. Post inflammatory hyperpigmentation did not occur to any patients. Acneiform eruption was observed after treatment in 1 patient out of 20 [5%]. Other side effects like petechiae, infections, milia, scaring, and post inflammatory hypopigmentation did not occur. Conclusion: Fractional carbon dioxide laser is effective in the improvement of atrophic facial acne scars with no recorded side effects.