Skin tumors are frequent in transplant patients, and their potential for progression (locoregional recurrences, metastases) is much greater than in the general population. The viral element with HPV probably represents one of the etiologic factors, although other only partially known factors play a role, including the sun and genetic factors. The high frequency of these skin tumors in transplant patients and their potential for progression require preventive and therapeutic measures: regular examination of the skin, strict advice about protection from sun exposure, excision of any suspect lesion, and treatment of warts that might be conducive to the development of skin cancers. Finally, it must be decided whether immunosuppression should be reduced or stopped during treatment of skin tumors with a high risk of progression.