Photodamaged skin occurs as a result of long-term exposure to ultraviolet radiation. The incidence of photodamage in European and North American populations with Fitzpatrick skin types I, II, and III is estimated at 80% to 90%. We conducted a double-blind clinical trial to test the efficacy and safety of 0.1% isotretinoin versus vehicle cream in 800 patients with moderate to severe photodamaged skin. Patients applied either 0.1% isotretinoin or matching vehicle cream to the face, forearms, and hands once nightly for 36 weeks. Local irritation and adverse events were assessed, and plasma retinoid levels were measured before and during treatment. Treatment response increased throughout the 36-week treatment period and the overall appearance of photodamaged skin was significantly better than with the vehicle alone. Topical application of 0.1% isotretinoin is an effective and well-tolerated treatment leading to clinically apparent improvement in the appearance of photodamaged skin of the face, forearms, and hands. (J Am Acad Dermatol 2000;42:56-63.)