Perovskite types Ba1-xMgxTi0.6Zr0.4O3 (With x=0.0, 0.07, 0.14) ceramics have been prepared through solid state reaction route. The room temperature XRD study suggests the compositions have single phase cubic symmetry. Microstructural studies have shown a step decrease in grain size. The dielectric study revels that the materials are of relaxor type and undergoes a diffuse type ferroelectric phase transition. The diffusivity increase with increase in Mg contents in the studied composition range. The transition temperature decreases with increase in Mg contents due to the decrease in grain size. (c) 2006 Published by Elsevier B.V.