Electrical conduction mechanism of LaNixFe1-xO3-delta and LaNixMn1-xO3+delta expected as Sr-free new cathode material for solid oxide fuel cells was analyzed. Electrical conduction behaviors of both specimens could be well fitted by small polaron hopping conduction model. The electrical conductivity of LaNixFe1-xO3-delta increased with increasing Ni content, showing agreement with decrease of activation energy for hopping conduction. The decrease of electrical conductivity and increase of activation energy of LaNixMn1-xO3+delta were observed with increasing Ni content for 0.0 <= x <= 0.4. Further Ni substitution increased electrical conductivity and decreased activation energy for 0.4 <= x <= 0.6. It was revealed using iodometry that the difference of hole carrier density between LaNixFe1-xO3-delta and LaNixMn1-xO3+delta was small. It was suspected that the origin of the difference of electrical conduction behavior of LaNixFe1-xO3-delta and LaNixMn1-xO3+delta was difference of energy level of e(g) band composed of Fe 3d or Mn 3d orbitals and their overlapping quantity with O 2p and Ni 3d band. (C) 2015 Elsevier Ltd. All rights reserved.