OBJECTIVE: To clarify in vivo healing of eyelid skin after carbon dioxide (CO2) laser resurfacing. DESIGN: Patients requesting upper eyelid blepharoplasty consented to undergo previous CO2 laser skin resurfacing of the upper eyelid skin segments to be excised at various time intervals. After blepharoplasty, the skin specimens were analyzed histopathologically by 2 masked pathologists. PATIENTS: Eight patients with Fitzpatrick skin types I and II. INTERVENTION: Upper eyelid CO2 laser resurfacing 1,2, 4, or 12 weeks before planned upper eyelid blepharoplasty. MAIN OUTCOME MEASURES: Epidermis: thickness, polarity, contour, and constituents. Dermis: repair zone thickness, vascular and inflammatory pattern, collagen deposition, and elastic fiber changes. RESULTS: The epidermis regenerated within 7 to 10 days. By 3 months, the epidermis revealed flattening of the rete peg pattern with restoration of polarity, keratinocytes, and melanocytes. The 3-month dermis demonstrated a fibrotic repair zone (500-700 microm), new elastic fibers, and telangiectatic capillaries. CONCLUSIONS: Eyelids heal similarly to other skin regions treated by CO2 laser resurfacing. This cutaneous healing is analogous to that previously reported with use of chemical peels. Histological changes may explain the skin smoothing and wrinkle reduction seen clinically.