Gangliosides were isolated front Trypanosonia brucei and analyzed by thin-layer chromatography (TLC) and TLC immunostaining test. Four species of gangliosides, designated as G-1, G-2, G-3, and G-4, were separated by TLC. G-1 ganglioside had the same TLC migration rate as GM3. In contrast, G-2, G-3, and G-4 gangliosides migrated a little slower than GM1, GD1a, and GD1b. respectively. To characterize the molecular species of gangliosides from T. brucci, G-1, G-2, G-3, and G-4 gangliosides were purified and analyzed by TLC immunostaining test with monoclonal antibodies against gangliosides. G-1 ganglioside showed the reactivity to the monoclonal antibody against ganglioside GM3. G-2 was recognized by the anti-GM1 monoclonal antibody. G-3 showed reaction with the monoclonal antibody to GD1a. G-4 had the reactivity to anti-GD1b monoclonal antibody. Using 4 kinds of monoclonal antibodies. we also studied the expression of GM3, GM1, GD1a, and GD1b in T. brucei parasites. GM3. GM1. GD1a. and GD1b were detected on the cell surface of T. brucei. These results suggest that G-1, G-2, G-3, and G-4 gangliosides are GM3 (NeuAcalpha2-3Galbeta1-4Glcbeta1-1Cer), GMI (Galbeta1-3GalNAcbeta1-4[NeuAcalpha2-3]Galbeta1-4GIbeta1-1Cer), GD1a (NeuAcalpha2-3Galbeta1-3Ga1NAcbeta1-4[NeuAcalpha2-3]Galbeta1-4Glcbeta1-1Cer). and GD1b (Galbeta1-3GalNAcbeta1-4[NecAcalpha2-8NeuAcalpha2-3]Galbeta1-4Glbeta1-1Cer), respectively, and also that they are expressed on the cell surface of T brucei.