Different anti-glycoconjugate auto-antibodies are described to be associated with peripheral neuropathies; the anti-MAG monoclonal IgM activity is determined by ELISA or immunoblotting essays, anti-glycolipid activity by ELISA or chromatography and monoclonal gammopathies by commercially available kits. These investigations are limited by possible cross-reactions due to the common glycosilate epitope. The peripheral neuropathies with anti-glycoconjugate auto-antibodies are different: Guillain-Barre syndrome and its variants (anti-GM1, GQ1b, LM1, GD1, GD1a gangliosides or sulfatides), motor neuropathy (anti-GM1 ganglioside), sensory neuropathies (anti-GD3, GD1b, GD1a, GQ1b gangliosides or sulfatides), and chronic myelinic neuropathy with IgM gammopathy (anti-MAG). We review the major clinical and electrophysiological features and discuss the underlying pathophysiological mechanisms.