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Electron-doped perovskite manganite Ca(0.9)R(0.1)MnO(3) (R= La, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Yb) polycrystalline samples were prepared and their transport and thermoelectric properties were studied from room temperature to 1000 K. The transport behavior for all the samples is adiabatic small polaron hopping mechanism below 600 K but changes to metallic conductivity at higher temperature. Above 600 K, more 3d electrons of Mn(3+) ions will occupy e(g) orbitals, resulting in the variation in thermoelectric power values. For all the samples, thermoelectric power is only determined by carrier concentration, but resistivity also rests with effective bandwidth. The size matching between Ca(2+) and R(3+) ions together with heavier R(3+) doping can improve thermoelectric performance evidently. Combining these two factors, Ca(0.9)Dy(0.1)MnO(3) and Ca(0.9)Yb(0.1)MnO(3) reach ZT=0.2 at 1000 K, suggesting that they can be efficient high temperature n-type thermoelectric oxide materials. (c) 2008 American Institute of Physics. [DOI: 10.1063/1.3003065]