We determined the incidence of venocclusive disease of the liver (VOD) in 96 recipients of autologous bone marrow transplants (BMT) to be 9.4%, a figure less than that reported for allogeneic transplantation. The development of VOD was compared in a cohort of 21 autologous BMT recipients and in 56 randomly chosen, comparably conditioned, concurrent allogeneic BMT recipients. One of these 21 (4.8%) autologous recipients developed VOD, versus 14 of 56 (25%) allogeneic recipients (P less than 0.05). Logistic regression analysis confirmed pretransplant hepatocellular dysfunction as a risk factor for VOD, and suggested that the use of methotrexate and/or cyclosporine contributes to the development of VOD after chemoradiation therapy. However, a graft-versus-host reaction cannot be excluded as a cause of the higher incidence of VOD in allogeneic recipients.