The transport properties of the NiO-Pd composites have been investigated by ac electrical conductivity measurements at various temperatures between 700-degrees-C and 1200-degrees-C in pure oxygen, air and purified argon atmosphere. The electrical conductivity of the composites at first decreases to 2.3 vol% Pd-NiO composition and then increases as a function of the volume fraction of Pd due to the decrease of the potential barrier in the space charge regions. The frequency dependance and the effects of the second phase in these composites have been characterized with impedance spectroscopy. In the complex resistivity plots of the 2.3 vol% Pd-dispersed NiO composite, the low-frequency semicircle decreases compared to that of undoped, polycrystalline NiO and it is proposed that the potential barrier in the space charge layer generated at the interface between Pd second phase and NiO matrix influences the bulk resistivity.