Normal co-ordinate analysis has been realised in the crystalline state using a modified Urey-Bradley-Shimanouchi force field combined with an intermolecular potential energy function that includes van der Waals interactions, some electrostatic terms and an explicit hydrogen bond function. The vibrational spectra of the α-l-fucose molecule have been recorded in the crystalline state, in the 4000-500 cm - 1 spectral region for the mid-IR spectra, in the 500-100 cm - 1 spectral region for the far-IR spectra, and in the 4000-20 cm - 1 spectral range for Raman spectra. These spectra constitute the experimental support for the establishment of a force field for the molecule in the crystalline state through a normal co-ordinate analysis.