In this study the comparative TLC immunostaining investigation of neutral GSLs and gangliosides from human skeletal and heart muscle is described. A panel of specific polyclonal and monoclonal antibodies as well as the GM1-specific choleragenoid were used for the overlay assays, combined with preceding neuraminidase treatment of gangliosides on TLC plates. This approach proved homologies but also quantitative and qualitative differences in the expression of ganglio-, globo- and neolacto-series neutral GSLs and gangliosides in these two types of striated muscle tissue within the same species. The main neutral GSL in skeletal muscle was LacCer, followed by GbOse3Cer, GbOse4Cer, nLcOse4Cer and monohexosylceramide, whereas in heart muscle GbOse3Cer and GbOse4Cer were the predominant neutral GSLs beside small quantities of LacCer, nLcOse4Cer and monohexosylceramide. No ganglio-series neutral GSLs and no Forssman GSL were found in either muscle tissue. GM3(Neu5Ac) was the major ganglioside, comprising almost 70% in skeletal and about 50% in cardiac muscle total gangliosides. GM2 was found in skeletal muscle only, while GD3 and GM1b-type gangliosides (GM1b and GD1α) were undetectable in both tissues. GM1a-core gangliosides (GM1, GD1a, GD1b and GT1b) showed somewhat quantitative differences in each muscle; lactosamine-containing IV3Neu5Ac-nLcOse4Cer was detected in both specimens. Neutral GSLs were identified in TLC runs corresponding to e.g. 0.1 g muscle wet weight (GbOse3Cer, GbOse4Cer), and gangliosides GM3 and GM2 were elucidated in runs which corresponded to 0.2 g muscle tissue. Only 0.02 g and 0.004 g wet weight aliquots were necessary for unequivocal identification of neolacto-type and GM1-core gangliosides, respectively. Muscle is known for the lowest GSL concentration from all vertebrate tissues studied so far. Using the overlay technique, reliable GSL composition could be revealed, even from small muscle probes on a sub-orcinol and sub-resorcinol detection level. Abbreviations: ATCC, American Type Culture Collection; GSL(s), glycosphingolipid(s); HPLC, high performance liquid chromatography; HPTLC, high performance thin layer chromatography; Neu5Ac, N-acetylneuraminic acid; Neu5Gc, N-glycolylneuraminic acid ; PBS, phosphate buffered saline. The designation of the following glycosphingolipids follows the IUPAC-IUB recommendations  and the ganglioside nomenclature system of Svennerholm . Lactosylceramide or LacCer, Galβ1-4Glcβ1-1Cer; gangliotriaosylceramide or GgOse3Cer, GalNAcβ1-4Galβ1-4Glcβ1-1Cer; gangliotetraosylceramide or GgOse4Cer, Galβ1-3GalNAcβ1-4Galβ1-4Glcβ1-1Cer; globotriaosylceramide or GbOse3Cer, Galα1-4Galβ1-4Glcβ1-1Cer; globoside or globotetraosylceramide or GbOse4Cer, GalNAcβ1-3Galα1-4Galβ1-4Glcβ1-1Cer; Fo or Forssman GSL, GalNAcα1-3GalNAcβ1-3Galα1-4Galβ1-4Glcβ1-1Cer; paragloboside or lacto-N-neotetraosylceramide or nLcOse4Cer, Galβ1-4GlcNAcβ1-3Galβ1-4Glcβ1-1Cer; lacto-N-norhexaosylceramide or nLcOse6Cer, Galβ1-4GlcNAcβ1-3Galβ1-4GlcNAcβ1-3Galβ1-4Glcβ1-1Cer; GM3, II3Neu5Ac-LacCer; GM2, II3Neu5Ac-GgOse3Cer; GM1 or GM1a, II3Neu5Ac-GgOse4Cer; GM1b, IV3Neu5Ac-GgOse4Cer; GD3, II3(Neu5Ac)2-LacCer; GD1a, IV3Neu5Ac,II3Neu5Ac-GgOse4Cer; GD1b, (II3Neu5Ac)2-GgOse4Cer; GD1α, IV3Neu5Ac,III6Neu5Ac-GgOse4Cer; GT1b, IV3Neu5Ac,II3(Neu5Ac)2-GgOse4Cer; GQ1b, IV3(Neu5Ac)2, II3(Neu5Ac)2-GgOse4Cer.