The conformational behaviour of sulfatide and its C-glycosyl analogue has been studied by using a combination of J and NOE data assisted by molecular mechanics calculations. There is a major exoanomeric conformation around the phi angle of both molecules with two or three conformers contributing to the equilibrium around psi. The MM3* calculations only provide a qualitative description of the actual population distribution. Despite this geometrical similarity, the quantitative analysis of the NOE intensities at a variety of mixing times indicates that the motion around the pseudoglycosidic linkages of the C-glycosyl analogue is faster than that for the natural compound.