Electrical behavior of a few compositions withx0.50 in the system La1−xNaxCo1−xNbxO3has been studied by complex‐plane‐impedance analysis in the temperature range 300–525 K. Three depressed semicircular arcs have been observed in the complex impedance plot of the composition withx= 0.50. These arcs represent the contributions of bulk, grain boundaries, and electrode polarization to the total observed resistance. Two semicircular arcs have been observed in the complex‐impedance plot of the compositions withx= 0.70 and 0.80. They represent the bulk and the grain boundaries contribution to the total observed resistance. The values of the resistance for the bulk and grain boundaries in each sample indicate the formation of barrier layers in thes