Ca3−xNdxCo4Oy polycrystalline thermoelectric ceramics with small amounts of Nd have been synthesized by the classical solid state method. X-ray diffraction data have shown that all the Nd has been incorporated into the Ca3Co4O9 and Ca3Co2O6 phases and no Nd-containing secondary phases have been produced. Apparent density measurements have revealed that all samples are very similar, with densities around 70 % of the theoretical one. Electrical resistivity decreases in all Nd-doped samples, compared with the pure one, while Seebeck coefficient remains constant for all samples. The improvement in resistivity leads to higher power factor values than the obtained for the undoped samples.