Introduction: Atrophic acne scarring, a common sequela of acne, can be treated by different interventions, including microneedling and laser resurfacing. Objectives: We sought to evaluate the comparative efficacy of microneedling versus fractional CO2 laser in treating atrophic acne facial scars using imaging with high and ultra-high frequency ultrasound. Methods: Participants received 2 sessions, separated by 1 month, of microneedling on the left side of the face and fractional CO2 laser on the right. Color Doppler ultrasound evaluations (24 and 70 MHz) were conducted at baseline and 3 months after treatment. Each patient completed questionnaires on satisfaction, pain, and adverse effects. Results: Nine subjects were enrolled. The frequency order of scar types was boxcar, ice-pick, and rolling. At 3 months, using the acne scar clinical evaluation scale, a decrease in scar scores of both methods was observed for total scars (P = 0.0005), ice-pick scars (P = 0.0128), and rolling scars (P = 0.0007). Twenty-two scars analyzed by ultrasound demonstrated a trend to decrease in size; however, no significant changes were observed for either microneedling or CO2 laser treatments. Moreover, there were no significant differences between these methods. Both treatments were rated as good or very good by patient assessments. There was a low frequency of pain and hyperpigmentation reported with both modalities, albeit somewhat higher with microneedling. Conclusions: Both microneedling and CO2 laser improved atrophic acne scars. Ultrasound did not show significant differences between these modalities.