A case of transmission of a glioblastoma multiforme from the donor to a kidney transplant recipient in the absence of previous ventriculosystemic shunt is described. The recipient was a 48-year-old woman who developed a fever with no other associated symptoms 17 months posttransplant. Physical examination revealed a large nonpulsatile mass on the upper graft pole. Histopathologic examination showed a highly cellular neoplasm with fusiform and globoid cells, a high grade of nuclear pleomorphism and mitosis, necrosis with pseudopalisading, and vascular proliferation. Immunohistochemistry of the cells showed them to contain glial fibrillary acidic and S-100 proteins, consistent with a glioblastoma multiforme. We conclude that the risk of tumor transmission from donors with primary central nervous system tumors to kidney transplant recipients, is real and should be considered when evaluating a graft mass in such patients.