Longer and better survival of End-Stage Renal Disease (ESRD) patients undergoing renal replacement therapy (RRT) is now associated with a higher prevalence of new elderly patients receiving renal replacement therapy (dialysis). In order to help clarify the association of cancer risk with RRT, the incidence of cancer in a population-based cohort of uraemic patients in the Region of Lombardy, northern Italy, was undertaken using data from the Lombardy Regional Dialysis and Renal Transplant Registry. A total of 479 cases of cancer of all sites was recorded in this population. There were statistically significantly elevated risks of primary liver cancer, kidney cancer, thyroid cancer, lymphoma and multiple myeloma. When the data were examined according to primary renal diseases, there did not appear to be any particular association between excess cancer risk and the underlying pathology. While some caution must be expressed in interpreting these data, due to the relatively small numbers of cases expected in many of the disease entities, the results indicate an excess of renal-cell and liver carcinomas and lymphomas in patients receiving RRT and highlight the necessity of careful follow-up and awareness of these associations, together with the need for early detection of such tumours.