LEED fine structure is found in LEED intensity curves at low energies below emergence thresholds for new diffracted beams. The fine structure is due to the interaction between a reflected beam and a beam which is totally internally reflected by the surface barrier. The fine structure may be strongly affected by chemisorption and this provides a useful technique for surface structural studies. The effects of surface roughening or smoothing, reconstruction and disordered adsorption can be clearly distinguished. Examples of the application of this technique to the oxidation of low index planes of Cu, Ni and W are discussed. It is concluded that LEED fine structure analysis provides valuable information which supplements that obtainable from other compatible surface science techniques.