Skeletal keratan sulphate has been fragmented using the enzyme keratanase II, and the complete ¹³C chemical shift data are reported for the four tetrasaccharides which derived from the repeat region. They have the structures: Galβ(1–4)GlcNAc(6S)β(1–3)Galβ(1–4)GlcNAc(6S)-ol, Gal(6S)β(1–4)GlcNAc(6S)β(1–3)Gal(1–4)GlcNAc(6S)-ol, Galβ(1–4)GlcNAc(6S)β(1–3)Gal(6S)β(1–4)GlcNAc(6S)-ol, and Gal(6S)β(1–4)GlcNAc(6S)(1–3)Gal(6S)β(1–4)GlcNAc(6S)-ol, where GlcNAc(6S)-ol represents N-acetyl-glucosaminitol-6-O-sulphate. The value of these data for microstructural analysis of undegraded keratan sulphate samples using ¹³C-NMR spectroscopy is discussed with respect to galactose sulphation levels and the block sulphation structure.