We have used the solid state reaction method to prepare Ca3 xSrxCo4O9 (CaCoO-Sr) polycrystalline samples (0 x 0;15), the obtained compound has an orthorhombic crystalline structure, where the lattice parameters do not change significantly with the Sr content. Their transport properties were studied from Seebeck coefficient S(T) and electrical resistivity (T) measurements as a function of the temperature and Sr content, in the temperature range between 100 and 290 K. The Seebeck coefficient is positive over the measured temperature range, wich suggests a conduction given by positive charge carriers, its magnitude decreases with the Sr content being temperature independent. The electrical resistivity exhibits a semiconducting behavior: its magnitude decreases with the Sr level up to reach values close to 5 m -cm. The thermoelectric power factor PF was obtained from measurements of S(T) and (T); it reaches maximum values close to 45 W/K 2 -cm. These results let us consider these kind of ceramics as promising thermoelectric compounds.