Sera from 40 patients with Guillain-Barré syndrome (GBS), including the subtypes acute inflammatory demyelinating polyneuropathy (AIDP), acute motor axonal neuropathy (AMAN), acute motor and sensory axonal neuropathy (AMSAN), and Miller Fisher syndrome (MFS) were examined for the presence of anti-ganglioside antibodies using the ganglioside agglutination assay, and the enzyme-linked immunosorbent assay (ELISA). In the ELISA system, sera were tested for IgM and IgG antibodies to GM1, GM2, GD1a, GD1b, GT1b, and GQ1b gangliosides. Antibodies to gangliosides were detected in 21 (53%) of the GBS patients by agglutination assay and in 17 (43%) of the patients by ELISA. Some of the sera reacted with more than one ganglioside. Antibodies were not found in the control sera that were studied. The agglutination assay may be useful for rapid screening of GBS sera for antibodies to multiple gangliosides.