Photodynamic therapy (PDT) is a treatment modality by highly reactive oxygen intermediates generated through the interaction of light with a photosensitizer. We treated actinic keratosis occurred on the face of a 65-year-old woman with topical PDT using 5-aminolevulinic acid (ALA) (MEDAC, Hamburg, Germany) and a 632nm diode laser (Creamoptec, Germany). 20% ALA was applied topically to the lesion sites which were then occluded for 6 hours. Light was administered at a wavelength of 632nm. The light intensity was 100mW/cm2 and the light dose was 100J/cm2. Although the diode laser was expensive, it was easy to handle the laser and the clinical results were excellent with respect to initial complete response and cosmetic outcome. There was only slight pain and a burning sensation during treatment.