We report a case of peripheral neuropathy occurring after autologous blood stem cell transplantation (ABSCT) for multiple myeloma. The patient, free of neurological symptoms, was transplanted in partial remission, and achieved a complete remission after transplantation. A severe peripheral, symmetric, distal sensori-motor polyneuropathy appeared at day 25 and worsened progressively until commencement of corticosteroid therapy. A peripheral nerve biopsy showed endoneurial cellular infiltrates which were predominantly composed of T cells identified by immunocytochemistry. Ultrastructural examination showed acute axonal damage. Electrophysiologic studies performed before and during the treatment were consistent with a severe axonal degeneration and showed a marked improvement, concomitant with the favorable clinical outcome. This is the first report of peripheral neuropathy after ABSCT.