Electrical resistivity ρ(T) and Seebeck coefficient S(T) measurements of polycrystalline La0.8Sr0.2Co1-x MnxO3 (0⩽x⩽0.1) (LSCoO) samples were carried out in the temperature range between 90 and 290 K. The samples were grown by citrate complex method; Seebeck coefficient and electrical resistivity were measured by differential technique and four-probe method, respectively. Both S(T) and ρ(T) increase monotonically with the Mn content, the electrical resistivity exhibit a metallic-semiconducting temperature behavior, while Seebeck coefficient is positive in whole measured temperature range. From S(T) and ρ(T) data it was possible to calculate the thermoelectric power factor PF, which in the samples with x=0.08, reaches values close to 18μW/K2cm; these values for PF are comparable with those of conventional thermoelectric materials, becoming these oxides in promissory thermoelectric materials.