Abstract. This paper is devoted to the study and the characterization of novel magneto-optical waveguides prepared via organic-inorganic sol-gel process. Thin silica/zirconia lms doped with magnetic nanoparticles were coated on glass substrate using dip-coating technique. After annealing, samples were UV-treated. Two dierent techniques were used to measure their properties: m-lines spectroscopy and free space ellipsometry. Results evidence low refractive index waveguides that combine a low modal birefringence (2 × 10 −4 ) with a Faraday rotation around 15• /cm (φ = 0.1%). The low birefringence is obtained with a soft UV treatement and a graded intrinsic anisotropy is evidenced for lms thicker than 5 µm. Therefore, we prove that the organic-inorganic sol-gel approach is very promising to realize magneto-optical waveguides with a nonreciprocal functionality such as TE-TM mode conversion.