In dermatologic oncology several good indications for radiotherapy are known. Precancerous lesions can be treated by grenz rays, as e.g. large senile (actinic) keratoses, lentigo maligna or large lesions of Bowen's disease or Queyrat's erythroplasia. Well-known indications are also mid-sized basal cell and squamous cell carcinomas, especially in the face of elderly patients. The lentigo-maligna melanoma should no longer be considered a radioresistant tumor, and it must be stressed that larger lesions can be successfully treated by radiotherapy. Dermato-radiotherapy shows also excellent palliative results, e.g. in cutaneous T-cell lymphomas such as mycosis fungoides, but also in Kaposi's sarcoma either of the classical type or AIDS-associated. In conclusion, radiotherapy is a good alternative treatment modality, especially in elderly patients, since it is painless and is possible on an outpatient basis with excellent functional results.