In recent years a novel problem has arisen in organ transplantation medicine, namely GVHD. The nervous system has been involved mainly at the level of the CNS and this can lead to a serious outcome for the patient. In rare cases, peripheral nerves may be affected and show acute or chronic polyneuropathy. Here a case is reported of polyneuropathy associated with chronic GVHD. A 32-year-old man, suffering from chronic GVHD following an allogeneic bone marrow transplantation (BMT) for malignant lymphoma at the age of 25, developed a motor dominant polyneuropathy 5 years later. Electrophysiologic studies demonstrated the demyelinating type of polyneuropathy. Biopsy specimens from skin and skeletal muscle disclosed perivascular lymphocytic infiltrates expressing T-cell markers. The sural nerve showed a loss of myelinated nerve fibers with epineurial fibrosis and rare occurrence of T cells, but without obvious vasculitic changes. The present case suggested that polyneuropathy could develop in association with chronic GVHD in some patients with a long-standing disease course.