Steady-state deformation of several important electronic ceramics, all having a perovskite structure, is reviewed and discussed in terms of their common prominent features. Of particular importance are the ferroelectric BaTiO3, a leading candidate for electrodes in solid-oxide fuel cells, (La1-xSry)(1-x)MnO3-delta, and the high-temperature superconductor YBa2Cu3Ox. In all cases, deformation occurs by grain-boundary sliding accommodated by diffusion. Cations are the rate-controlling species and their diffusivities can be calculated and compared to existing tracer diffusion data. In some cases, the tracer diffusion coefficients have not been measured, but measurements of steady-state creep can provide these values.