Compressive creep tests have been performed on perovskite-type Ba0.5Sr0.5Co0.8Fe0.2O3-delta ceramics. The activation energy, stress exponent and inverse grain size exponent of the steady-state creep rates are evaluated at p(O-2) = 0.21.10(5) Pa and 0.01.10(5) Pa in the stress, temperature and grain size ranges 5-20 MPa, 1078-1208 K and 2.5-17.4 mu m, respectively. The results indicate that the creep rate of Ba0.5Sr0.5Co0.8Fe0.2O3-delta is controlled by diffusion of cations via both the oxide lattice (bulk diffusion) and along grain boundaries. The creep rate of Ba0.5Sr0.5Co0.8Fe0.2O3-delta increases profoundly by more than one order of magnitude at 1153-1178 K, which is tentatively linked with the onset of the hexagonal-to-cubic phase transition in this compound. (C) 2009 Elsevier B.V. All rights reserved.