OBJECTIVE: This study reports the characteristics and surgical outcome of colorectal cancer in patients with chronic renal failure treated either by renal transplantation or dialysis. METHODS: Two thousand four hundred and seventeen patients with CRF (1387 transplant and 1030 dialysis) were treated at The Queen Elizabeth Hospital, South Australia, between January 1967 and September 2000. RESULTS: Fourteen have developed colorectal cancer and had their clinical records reviewed. Nine patients were renal transplant recipients and 5 patients were treated with dialysis. Eight patients had surgery. Chemotherapy was given palliatively to 3 patients. One patient died in hospital postoperatively. Seven patients with a renal transplant had notes available. Six presented with late stage disease and all were dead within 9 months of presentation from their disease. In the dialysis patients, tumour stage at presentation was not so advanced and although all the patients have died, the cause of death was secondary to the colorectal cancer in only 2 patients. CONCLUSIONS: This study highlights the poor outcome of patients who have had renal transplant and develop colorectal cancer. Immunosuppression and late diagnosis are implicated in this poor outcome.