7 (14%) out of 51 kidney-allograft recipients developed a total of 19 malignant skin tumours four to forty-five months after transplantation. Immunosuppressive treatment, known to be associated with an increased risk of development of tumours of lymphoreticular type, also enhances the occurrence of squamous-cell carcinoma. Under the influence of immunosuppression cutaneous hyperkeratoses more rapidly evolve into squamous-cell carcinoma, multiple skin cancers occur in some patients, and keratoacanthoma is not only more frequent but also prone to early recurrence.