The interaction of NO with TiO2 (110)-(1 x 2) surface has been studied by X- ray photoelectron spectroscopy, ultraviolet photoelectron spectroscopy, Auger electron spectroscopy, and low- energy electron diffraction, with the aim to clarify the role of ordered defects in NO reactivity toward TiO2. The interaction was studied for exposures up to 2000 L. However, the main effects occur already in the first 2 L. The exposure of the surfaces to NO resulted in the healing of defect sites without adsorption of N and low- energy electron diffraction shows that the surface (1 x 2) symmetry is not lost after the NO dose.