The oxide ion conductivity of LaNi0.6Fe0.4O 3 (LNF) was studied by oxygen isotope exchange measurement and SIMS at 673 ∼ 1073K in p(O2) = 0.4 ∼ 20 kPa. Oxygen tracer diffusion coefficients (D*) and the surface exchange rates (k) obtained were 4.3 × 10-9 cm2/s and 8.6 × 10 -6 cm/s respectively at 1073 K in p(O2) = 20 kPa. The activation energy (Ea) for D* was obtained as 152 kJ/mol. D* and Ea for D* of LNF are very close to those of La0.6Sr0.4Co0.8Fe0.2O3 (LSCF). Additionally, oxygen vacancy content in LNF lattice is estimated which are much less than that of LSCF. Possible mechanism of oxide ion conductivity/diffusivity in LNF is discussed according to the present results.