The effects ytterbium doping on the structure, microstructure, and dielectric properties of 0.86PbMg1/3Nb2/3O3+0.13PbTiO3+0.01La2O3+xYb2O3 were studied (x=0.5, 1.0, 1.5 and 2.0 mol%). The ceramics were prepared by the solid-state method. The structural and microstructural properties of the compounds were examined with X-ray diffraction and scanning electron microscopy. The results show an increase in the average grain size, permittivity, and diffusivity of the system as function of increasing Yb2O3 content. This trend was the result of incorporation of the rare earth ion at site B of the structure.