The incidence of squamous cell carcinoma of the lower lip in immunosuppressed renal-transplant recipients is considerably higher than in the normal population. In addition to immunosuppressive treatment, the most important risk factors for the development of lip cancer in these patients are exposure to sunlight and smoking habits. Regular surveillance of renal-transplant recipients and early biopsy of premalignant lesions of the lip allow early detection of lip cancer. Patients should also be advised to avoid unprotected exposure to sunlight, to use appropriate sunscreens and to stop smoking. Six cases of squamous cell carcinoma of the lower lip in renal-transplant recipients are described.