The electrical resistivity and thermoelectric power measurements of Zn-substituted Li-Mg ferrites having the general formula LixMg0.4Zn0.6-2xFe2+xO4 (where x=0, 0.05, 0.1, 0.15, 0.2, 0.25 and 0.3) were carried out from room temperature to 600 degrees C. The variation of log p with reciprocal of temperature shows a discontinuity at Curie temperature. The activation energy in the ferrimagnetic region is found to be lower than that in paramagnetic region. The conduction mechanism is explained on the basis of hopping of electrons. The variation of room temperature resistivity with composition indicates that resistivity initially decreases with Zn content up to 0.3 and then it increases with further increase in Zn content. The Curie temperature is found to decrease linearly with addition of Zn. The variation of Seebeck coefficient with temperature indicates that all the samples show n-type conductivity. (c) 2005 Elsevier B.V. All rights reserved.