The ganglioside composition of 15 cases of meningioma, 15 cases of astrocytoma, 5 cases of neurinoma, 4 cases of ependymoma, 3 cases of metastatic brain tumor and 1 case each of mixed glioma, oligodendroglioma, medulloblastoma, embryonal carcinoma, and cultured glioma cell line were analyzed by thin-layer chromatography. The GM2, GD3, and GD2 content of the tumors was determined using specific monoclonal antibodies (MAb). Cases were grouped according to the difference in ganglioside pattern and various clinical features. In meningiomas and astrocytomas, GM3 and GD3 were the major gangliosides. The tumor content of the rather simple gangliosides (GM3, GM2, GD3, GD2) increased or was almost equal to that of normal tissue (leptomeninges tissue in the case of meningiomas, and brain tissue in the case of astrocytomas), while the tumor content of complex gangliosides (GM1, GD1a, GT1a, GT1b) decreased as compared with normal tissue. The GM3 content of meningiomas increased in middle-aged patients, who comprised the majority of the patients with these tumors. The GD2 content decreased in middle-aged patients with initial symptoms of meningioma within a year. The GM3 content of astrocytomas decreased in patients who underwent radiotherapy. The amount of GM3 and GD3 increased in small tumors. GM3 may be related to the early proliferative stage. The ganglioside patterns of brain tumors are shown in this study to differ according to clinical features and also to be changeable in their clinical courses.