Lymphoproliferative disorders occur with a greater frequency in recipients of solid organ transplants. Unlike in the general population, these tumors tend to arise in extranodal sites and are often confined to a single organ. We report on a patient with lymphoproliferative disease confined to the hilum of the renal allograft. The only clinical clue to the presence of the tumor was an increase in the serum creatinine secondary to ureteral obstruction by the mass.