Abstract The materials La 0.7Ca 0.3− x K x MnO 3 ( x = 0.00 ; 0.05; 0.10) were prepared by the solid-state method. The electrical properties of these materials have been studied using dc and ac impedance spectroscopy technique. Impedance spectrum results indicate that the electrical properties are strongly dependent on temperature and have a good correlation with the sample microstructure in different temperature ranges. The ac conductivity spectrum is found to obey Jonscher’s universal power law. The loss tangent tan ( δ ) = ε ″ / ε ′ at different temperatures shows the possibility of hopping mechanism for electrical transport processes in the system.