To determine the applicability of LaCo1-xNixO3 in a conductive material for electrical wiring, the dependence of the electronic transport property on the Ni content is investigated via Hall effect measurements, Rietveld analyses, and band structure calculations. Ni doping (50 mol %) into the Co sites realizes a high electrical conductivity of 1.9 x 10(3) S/cm, which is an unexpectedly high value for a LaCo1-xNixO3 system, at room temperature due to the high carrier concentration of 2.2 x 10(22) cm(-3) and the small effective mass of 0.1 m(e). In addition, the high electrical conductivity is maintained from room temperature to 900 degrees C; that is, the temperature coefficient of the conductivity is smaller than that of standard metals. Thus, the results indicate that LaCo0.5Ni0.5O3 is suitable as a conductive material for electrical wiring at high temperatures in air.