The kinetics of surface and bulk electron−hole pair recombination have been measured separately on TiO₂(110) in ultrahigh vacuum under well-controlled surface conditions for the first time. Using 100 eV incident electrons, excitation of electron−hole pairs occurs within ∼6 Å of the surface, and the rate of stimulated desorption of O₂ was measured as a means of determining the charge carrier recombination kinetics, which are found to be mediated by the surface and to be first-order in charge carrier concentration. Comparison with a previous O₂ photodesorption experiment, where excitation by 3.4 eV photons was used for electron−hole pair generation in a deeper region below the surface (∼100 Å), shows that bulk recombination in TiO₂ occurs by second-order kinetics in charge carrier concentration.