The technique of mass-spectroscopic thermal analysis has been used to investigate the thermodesorption and thermodestruction of modifiers adsorbed on TiO2? (rutile) used as pigment and filler in polymer composites. Through identification of the products of the thermodesorption of butylamine, methanol, and acetic acid from the rutile surface with different degrees of hydroxylation, and through evaluations of the kinetic parameters of the processes by which these materials are evolved, more complete information has been gained, compared with data obtained by adsorption and spectral methods, on the mechanism of the adsorption interaction of modifiers with TiO2 surface, as well as on the thermal stability of modified pigments.