Recent studies have shown that antiganglioside antibody-mediated complement activation plays a key role in development of Guillain–Barré syndrome and related disorders. Additionally, complement-independent nerve dysfunction is suggested by in vitro studies, showing that antiganglioside antibodies directly inhibit voltage-gated Ca channel currents and change the integrity of lipid rafts. These pathogenic actions of antiganglioside antibodies might be governed by the avidity of the antibodies, which is influenced by specific localization of target gangliosides in the peripheral nervous system or glycolipid environment around the target antigens. The recent discovery of antibodies to ganglioside complexes has expedited the understanding of the mechanisms underlying antiganglioside antibody-mediated nerve dysfunction in Guillain–Barré syndrome and related disorders. In chronic immune-mediated neuropathy, some antiganglioside antibodies have also been identified as diagnostic markers, although their pathophysiological roles remain to be determined.