A long-term retrospective follow-up study was performed to evaluate the risk of skin cancer in 1098 renal transplant recipients in Queensland, Australia. In a subgroup, we also assessed the influence of immunosuppressive therapy on the risk of developing skin cancer: cyclosporine alone or in combination with prednisolone; azathioprine alone or in combination with prednisolone; or the combination of cyclosporine and azathioprine with or without prednisolone. The cumulative incidence of developing skin cancer, calculated by life table analysis, increased progressively from 7% after 1 year of immunosuppression to 45% after 11 years and to 70% after 20 years of immunosuppression. Multivariate analysis in a subgroup comparing the risk of developing skin cancer in patients on either long-term cyclosporine or azathioprine (each with or without prednisolone) and in patients on the combination of cyclosporine and azathioprine (with or with- out prednisolone) showed no differences between the groups. We conclude that it is likely that the increased risk of skin cancer associated with immunosuppression is independent of the agent(s) used and is a result of the immunosuppression per se.