The primary structure of the ceramide tetracontasaccharide (1) from rabbit erythrocyte membranes has been determined with the aid of 600-MHz two-dimensional phase-sensitive correlated, "totally correlated" (TOCSY, homonuclear Hartmann-Hahn), relayed coherence transfer, triple quantum filtered, and nuclear Overhauser enhancement 1H NMR spectra. It was shown that obtaining subspectra of the constituent sugar residues from a totally correlated spectrum and assigning the resonances occurring in these subspectra by analyzing the relevant cross-peaks in phase-sensitive correlated spectra is the most efficient way for establishing complex oligosaccharide structures. This analysis has shown 1 to be the highest homologue of the multiantennary neolactoglycosphingolipids of the following general formula with n = 7: (Formula: see text).