Thirty-seven consecutive renal transplant recipients were studied prospectively for joint disease. Six developed arthralgias while corticosteroid doses were being lowered. Eleven patients (30%) developed knee effusions at a mean interval of 10 days following transplantation. Synovial fluids were colorless or very pale yellow, with few leukocytes (mean, 28/mm3). These benign transudative effusions did not correlate with immunologic abnormalities, transplant rejection, crystal deposition, or avascular necrosis and may have been due to high dose oral corticosteroid therapy.Musculoskeletal complaints have been noted in up to 30% of patients receiving kidney transplants (1-4). Although aseptic necrosis has received the most atten-