Development of cancer on a kidney transplant is a rare complication of renal transplantation. In the light of a case of cancer on a kidney transplant, in a series of 729 consecutive renal transplantations performed between January 1987 and December 2000, the authors discuss the epidemiology, pathophysiology, prognosis, treatment and prevention of this disease and emphasize the importance of regular and prolonged periodic ultrasound surveillance of kidney transplants. The reference treatment is transplantectomy with discontinuation of immunosuppression and resumption of haemodialysis. Under certain conditions, partial transplantectomy could appear be an alternative to the reference treatment.