Attenuated total reflection Fourier transform infrared (FTIR-ATR) spectroscopy was used to follow the adsorption of the globular protein lysozyme from aqueous (D2O) solution onto a silicon surface. The effect of changing temperature and/or pD on the structure of protein in the adsorbed layer is observed and compared with the effect of these changes on concentrated solutions. We show that the same spectral changes as those occurring in the heat-set gelation of concentrated solutions of globular proteins can also be observed in adsorbed proteins, but at lower temperatures. We suggest that this is due to the presence of the surface having the effect of promoting molecular structural rearrangements.