We report a 4-year-old girl diagnosed as having Guillain-Barré syndrome after infection by Penner serotype 19 of Campylobacter jejuni. The patient had the HLA-B35 antigen. Neurological examination revealed distal-dominant weakness and intact sensation. Serial electrophysiological studies indicated that the predominant process was axonal degeneration involving motor nerves. An enzyme-linked immunosorbent assay revealed the presence of high titres of serum IgM antibodies to gangliosides GM1 and GM2. The IgM auto-antibody titres decreased concurrently with the clinical course of the illness and no switching from IgM to IgG secretion took place.