Guillain-Barré syndrome (GBS) has been rarely reported after liver transplantation and generally has good outcome. We report a liver transplant patient on FK506 (tacrolimus) who developed GBS 6 months after liver transplantation. There was no evidence of liver rejection or active infection. Despite treatment with intravenous immunoglobulin, the patient expired. GBS occurred despite downregulation of T cells by FK506, suggesting that humoral dysfunction might be the predominant mechanism of GBS in this report.