Three of the most frequent cancers occurring in transplant recipients affect the skin: Kaposi's sarcoma and spino- and baso-cellular carcinomas. The two latter neoplasms are often preceded by precancerous lesions such as keratosis, warts, porokeratosis and keratoacanthomas. We describe the clinical presentations of these lesions and detail the possible therapies in each case: local treatment, surgery, modulation of immunosuppression, and chemotherapy.