Photorefractive planar waveguides in LiTaO3 are fabricated by both a proton exchange and a successive copper exchange. The influence of different fabrication steps on the refractive index profile and optical absorption is investigated. The holographic efficiency is determined together with the dark- and photo-conductivity. We show that the photorefractive properties of proton-exchanged LiTaO3 waveguides are considerably improved by the additional copper exchange. It is established that the holographic efficiency depends on the copper content, the phase of the proton-exchanged layer and the light intensity. © Springer-Verlag 1997.