In this letter, we report on optical channel waveguides in Nd:YV O4 crystals produced by photographic masking and following direct O+ ion implantation at 3.0 MeV. Annealing treatments of the samples are performed to improve the waveguide stability and to reduce losses. An increase of the ordinary refractive index induced by the implantation is believed to be responsible for waveguide formation. Quasi-TM guided modes are observed, while no quasi-TE ones are detected. The optical damping coefficients are of 0.43, 0.63, and 0.54 cm-1 for channel waveguides with widths of 4, 5, and 6 μm, respectively. The result of modal analysis is in agreement with the experimental data. © 2006 American Institute of Physics.