Nb-doped anatase TiO2 films were deposited on unheated glass by dc magnetron sputtering using slightly reduced Nb-doped TiO2-x targets (Nb concentration: 3.7 and 9.5 at. %) with various hydrogen or oxygen flow ratios. After postannealing in a vacuum (6 x 10(-4) Pa) at 500 degrees C for 1 h, both films were crystallized into the polycrystalline anatase TiO2 structure. The resistivity decreased from 1.6 X 10(-3) to 6.3 X 10(-4) Omega cm with increasing Nb concentration from 2.8 to 8.0 at. %, where the carrier density increased from 5.4 X 10(20) to 2.0 X 10(21) cm(-3) and the Hall mobility was almost constant at 5-7 cm(2) V-1 s(-1). The films exhibited a high transparency of over 60%-80% in the visible region. (C) 2010 American Vacuum Society. [DOI: 10.1116/1.3358153]