We report the magnetic, Mössbauer spectroscopy and resistivity measurements in order to understand the electronic behaviour of bulk Co0.2Zn0.8Fe2O4 spinel oxide. The effect of magnetic order on electrical behaviour is observed from the resistivity measurements in the absence and presence of magnetic field. The analysis of Mössbauer spectra suggests the absence of Fe2+ ions in the system, which implies that complete hopping of charge carriers between localized Fe3+/Co2+ and Fe2+/Co3+ pair of ions in B sublattice is not the favourable mechanism in Co0.2Zn0.8Fe2O4. We suggest that electrical behaviour of the present sample may be consistent with a model of fractional charge transfer via FeB3+-O2--CoB2+ superexchange path. © 2007 Elsevier B.V. All rights reserved.