Electrical conductivities of complex perovskites, layered perovskite and Sr doped layered perovskite oxides were measured and analyzed for cathode materials of Intermediate Temperature-operating Solid Oxide Fuel Cells (IT-SOFCs). The electrical conductivities of $Sm_{1-x}Sr_xCoO_{3-delta}$ (x = 0.3 and 0.7) exhibit a metal-insulator transition (MIT) behavior as a function of temperature. However, $Sm_{0.5}Sr_{0.5}CoO_{3-delta}$ (SSC55) shows metallic conductivity characteristics and the maximum electrical conductivity value compared to the values of $Pr_{0.5}Sr_{0.5}CoO_{3-delta}$ (PSC55) and $Nd_{0.5}Sr_{0.5}CoO_{3-delta}$ (NSC55). The electrical conductivity of $SmBaCo_2O_{5+delta}$ (SBCO) exhibits a MIT at about $250^{circ}C$. The maximum conductivity is 570 S/cm at $200^{circ}C$ and its value is higher than 170 S/cm over the whole temperature range tested. $SmBa_{0.5}Sr_{0.5}Co_2O_{5+delta}$ (SBSCO), 0.5 mol% Sr and Ba substituted at the layered perovskite shows a typically metallic conductivity that is very similar to the behavior of the SSC55 cathode, and the maximum and minimum electrical conductivity in the SBSCO are 1280 S/cm at $50^{circ}C$ and 280 S/cm at $900^{circ}C$.