The human glioma cell line D-54 MG and one of its single-cell-derived clones exhibit some properties of oligodendroglia, including surface antigens, enzymatic activity, and absence of markers for astrocytes. The glioma cells were further examined for glycolipids characteristic of oligodendroglia. The glioma cells had only about 2% of the total lipids as galactolipids while oligodendroglia have 10%. Incorporation studies showed only 25% of the incorporation of galactose into galactolipids as found in oligodendroglia. Sphingomyelin and phosphatidylinositol appeared to be increased. Several phospholipids exhibited high levels of incorporation of substrates, e.g., phosphatidylcholine and phosphatidylinositol. The ganglioside patterns were much less complex for the glioma cells. Thus, the glioma cells have greatly decreased amounts of glycolipids when compared to oligodendroglia. This finding is consistent with the theory that the loss of glycolipids on the cell surface may lead to the loss of regulation of contact inhibition.