The cubic perovskite BaNbO3 has been prepared in sealed ampoules from mixtures of BaO, NbO2 and Nb, in different ratios. The Ba and O contents, determined by thermogravimetry, X-ray and neutron diffraction, are always close to the stoichiometric values. Resistivity and magnetic measurements indicate that BaNbO3 behaves as a metal, showing a high room-temperature resistivity and a Pauli-like behavior. This suggests an important electronic delocalization in this system. The enhanced value of the Pauli susceptibility indicates a relatively strong correlation among the 4d electrons in narrow pi* conduction bands of T2g parentage.