SUMMARYThe effect of P and V contents on the microstructure and thermoelectric properties of Fe 2-x M x O 3 (M: P and V; 0 ≤ x ≤ 0.01) is studied. Higher P and V contents result in increases of both the grain size and density, thus increasing the electrical conductivity. The absolute values of the Seebeck coefficients of the Fe 2-x P x O 3 and Fe 2-x V x O 3 increase with increasing P and V contents up to x = 0.0075 and 0.005, respectively, and then decrease with further increase of its concentration. The addition of a small amount of V (0.005) to Fe 2 O 3 leads to a marked increase in both the electrical conductivity and Seebeck coefficient. This means that the introduction of a small amount of V is highly effective for improving the thermoelectric properties of Fe 2 O 3 .