P-type perovskite oxides La1-xSrxCoO3 (0 <= x <= 0.2) have been prepared using a polymerlized complex method and sintering. The Seebeck coefficient, electrical conductivity, and thermal conductivity of the oxides were studied from room temperature to 773 K. The ln(sigma T)-1/T relationships revealed small-polaron hopping mechanism for the higher Sr contents. Large Seebeck coefficients were observed in lightly Sr-doped samples. Sr doping greatly reduced the Seebeck coefficient and enhanced the electrical and thermal conductivity of the samples. The temperature-induced spin-state transition of Co3+ ions strongly influenced the transport properties. The highest ZT value found in this series of oxides was 0.046 at 300 K for x = 0.1.