Skin cancer is the most common human carcinoma. There has been a dramatic increase of the incidence over the last decades. This trend is very likely caused by the increased UV-light exposition of the population. Whereas basalioma and spinalioma as the most frequent types of skin cancer have a low mortality, the bad prognosis of malignant melanoma is the reason for the 100% increase of the mortality rate over the last ten years. Cancer prophylaxis means the early detection of precancerous or suspect lesions. Popular information on the risk and a more generous indication for excision are the best instruments to lower the mortality of skin cancer.