Conductivity measurements indicate that lanthanum nickel ferrite (LaNi0.6Fe0.4O3) is a potential cathode current collector material in solid oxide fuel cells (SOFCs). However it is known that lanthanum nickel ferrite reacts with zirconia, commonly employed in SOFCs, to form lanthanum zirconate at typical manufacturing temperatures. The reaction product, which has a low electrical conductivity, may therefore compromise the use of lanthanum nickel ferrite as a cathode current collector in SOFCs that employ a lanthanum strontium manganite-zirconia composite cathode, such as the Rolls-Royce Integrated Planar (IP)-SOFC. Thus the interaction of lanthanum nickel ferrite with lanthanum strontium manganite ((La0.85Sr0.15)(0.90)MnO3) and 3 mol% yttria-stabilised zirconia has been investigated by powder X-ray diffraction, electrochemical impedance spectroscopy, electron microscopy and energy dispersive spectroscopy. While no interfacial lanthanum, zirconate product was detected, it was found that interdiffusion of manganese and nickel occurred between the perovskite phases of the cathode and current collector layers. Results of electrochemical impedance spectroscopy suggest that the interaction has a strong detrimental effect on cathode performance in the long-term. (C) 2008 Elsevier B.V. All rights reserved.