Skin cancers are a significant medical problem for organ-transplant recipients. Squamous cell carcinoma and basal cell carcinoma are most common tumors. An increasing incidence of melanoma, Kaposi sarcoma, Merkel cell carcinoma, as well as uncommon skin malignancies, is also seen. Predisposing factors include cumulative sun exposure, cumulative immunosuppression, age, gender, skin type, virus detection and genetic alterations. Skin tumors grow rapidly and their number continues to increase in the years following transplantation. Large numbers of tumors, aggressive courses and appearance in young patients are other characteristics of these skin tumors. More general awareness of the need for preventive measures and regular dermatological examinations is desirable. In addition standardized registries are needed to assure the comparability of data, to better correlate immunosuppression with skin tumors and to plan therapeutic studies.