Background and Objective: Due to the significant risk profile associated with traditional ablative resurfacing, a safer and less invasive treatment approach known as fractional deep dermal ablation (FDDA™) was recently developed. We report the results of the first clinical investigation of this modality for treatment of photo- damaged skin. Study Design/Materials and Methods: Twenty-four subjects received treatments on the inner forearm with a prototype fractional CO2laser device (Reliant Technologies Inc., Mountain View, CA) at settings of 5-40 mJ/MTZ and 400 MTZ/cm2. Clinical and histological effects were assessed by study investigators 1 week, 1 month, and 3 months following treatment. Thirty subjects were then enrolled in a multi-center study for treatment of photo- damage using the same device. Subjects received 1-2 treatments on the face and neck, with energies ranging from 10 to 40 mJ/MTZ and densities ranging from 400 to 1,200 MTZ/cm2. Study investigators assessed severity of post-treatment responses during follow-up visits 48 hours, 1 week, 1 month, and 3 months following treatment. Using a standard quartile improvement scale (0-4), subjects and investigators assessed improvement in rhytides, pigmentation, texture, laxity and overall appearance 1 and 3 months post-treatment. Results: Clinical and histologic results demonstrated that fractional delivery of a 10,600 nm CO2laser source offers an improved safety profile with respect to traditional ablative resurfacing, while still effectively resurfacing epidermal and dermal tissue. Forearm and facial treatments were well-tolerated with no serious adverse events observed. Eighty-three percent of subjects exhibited moderate or better overall improvement (50-100%), according to study investigator quartile scoring. Conclusions: FDDA™ treatment is a safe and promising new approach for resurfacing of epidermal and deep dermal tissue targets. Lasers Surg © 2009 Wiley-Liss, Inc.