Several aspects of the relationships between glycolipids, gliomas, and problems involved in studying these are reviewed. Major problems that currently must be addressed include developing a classification scheme that more accurately predicts the biological behavior of these tumors, obtaining samples representative of the patient's glioma, and identifying appropriate control specimens. Results of analytical studies indicate that the patterns of gangliosides in human glioma tissues generally correlate with the degree of histological malignancy. Some gliomas contain unusual, and perhaps unique, glycolipids. Exogenous glycosphingolipids can alter cell shape and growth, which may involve modulation of growth factor receptors and protein kinases. Tumor glycolipids may also modulate immune functions in patients harboring gliomas. Transfection of nonneural cells with some oncogenes can alter glycolipid metabolism, which may be part of the mechanism through which these oncogenes exert their effects.