Abstract Co-doping effect of Sm3+ and Ca2+ ions in ceria has been studied using the microwave assisted synthesis (MAS) technique. Thermal response of the prepared compositions was studied using differential thermal and thermo-gravimetric techniques (DTA/TG). Structural studies were performed using X-ray diffraction (XRD) and fourier transform infrared spectroscopy (FT-IR). The impedance analyses were performed over a wide range of temperatures (200–500°C) and frequency (100Hz to 1MHz). The conductivity data show that 10% doping of both Sm3+ and Ca2+ in ceria provides a significant rise in the conductivity value of pure ceria.