Microstructural characteristics and the corresponding resistivity-temperature (ρ−T) properties of microwave- and conventionalsintered Pb0.6Sr0.4TiO3 materials with positive temperature coefficient of resistivity (PTCR) were investigated in the present work. The specimens prepared by microwave sintering exhibited a single Tc, whereas those prepared using conventional sintering show double Tc behavior. During the microstructural investigations, sintering aids, SiO2 and TiO2, showed intriguing liquid phase sintering characteristics in the specimens. Large amounts of Pb-species dissolved in high Si regions, where a nonequilibrium core-shell structure was frequently observed, especially for microwave sintered specimens, which showed very complicated domain arrangements in the grain interiors.