Rutherford backscattering in the channeling alignment was used to characterize the damage produced in rutile TiO2 by oxygen ion implantation at energies of 200 and 400 keV. Backscattering g{om the dajnaged layer increases sublinearly with ion dose above 4×1015 ions/cm2. Complete amorphization was not achieved even for much higher doses and implant temperatures well below room temperature, and remnants of the original crystal lattice remain in the damaged layer. Substantial defect annealing occurs at 450 C, and essentially complete lattice recovery is observed at 750 C when the annealing takes place in a reducing environment. In an oxidizing ambient, higher annealing temperatures are required to achieve the same degree of crystal regrowth, and dechanneling actually increases at lower annealing temperatures, apparently due to the coalescence of point defects into extended defects. The optical properties of the implanted layer were also probed by ellipsometry.