Nuclear magnetic resonance properties are shown to be in good accord with those that are expected for synthetic oligosaccharides in the conformations which are predicted by hard-sphere molecular modelling and taking into consideration the important contribution by the exo-anomeric effect. The studies involve first a comparison of the β D Gal(1 → 3)β D GlcNAc (Type 1) and β D Gal(1 → 4)β D GlcNAc (Type 2) disaccharide structures based mainly on 13 Cmr and then an examination of the relationships between the calculated conformations and 1 Hmr and 13 Cmr parameters for human blood group determinants which are derived from the Type 1 core disaccharide. Among the structures examined are the di-, tri-, and tetrasaccharides for the ABH and Lewis antigenic determinants. Certain immunological–conformational relationships are noted.