The gangliosides of carp intestinal mucosa were isolated and analysed by thin-layer chromatography (TLC), TLC immunostaining test, and TLC/secondary ion mass spectrometry (TLC/SIMS). Four species of gangliosides, designated as G-1, G-2, G-3 and G-4, were separated on TLC. The TLC/SIMS analysis of the G-1 ganglioside of carp intestinal mucosa revealed a series of [M-H](-)ions from m/z 1061 to m/z 1131 representing the molecular mass range of GM4-like ganglioside with NeuAc. G-2, G-3 and G-4 gangliosides were analysed by the TLC immunostaining test. G-2 ganglioside was recognised by the monoclonal antibody specific for ganglioside GM1 (AGM-1 monoclonal antibody). However, G-3 ganglioside migrating on TLC between GM3 and GM1 ganglioside was not recognised by anti-GM3 monoclonal antibody and by AGM-1 monoclonal antibody. Furthermore, G-4 ganglioside with a similar TLC mobility as GD1a ganglioside did not show the reactivity to the anti-GD1a monoclonal antibody. In addition using the AGM-1 monoclonal antibody, the expression of GM1 ganglioside in the carp intestinal tissue was studied. GM1 ganglioside was detected on the epithelial cell surface of carp intestinal mucosa.