A Fourier transform infrared-attenuated total reflection (FTIR-ATR) spectroscopy study of the photodegradation of adsorbed bovine Serum Albumin (BSA) on porous TiO2 films was carried out. The experiments were performed in a flow-through cell in water at concentrations of 10-6 mol/L at room temperature. The curve fitting method of the second derivative spectra allowed us to explore details of the secondary structure of pure BSA in water and conformation changes during adsorption and illumination processes. The results clearly demonstrate that the amount of adsorbed BSA decreased under UV illumination although adsorption without illumination is considered as irreversible. The influence of irradiation on the adsorption is not yet well understood. Also, during illumination of adsorbed BSA dissolved CO2 at 2341 cm-1 was observed, which indicates that part of the BSA is mineralized. The analysis of second derivative of infrared spectra was used to obtain direct quantitative information on the secondary structure components of BSA which show that the percentage of a-helix decreases from around 63% to 54% during UV light illumination whereas the percentage of b-turn increases.