Effects of the oxygen partial pressure within the Ar process plasma and the annealing treatment on the properties of magnetron sputtered In0.025Cd0.975O films were investigated in detail. It was observed that the electrical resistivity drastically increases with the oxygen addition, from 4.8 x 10(-5) Omega.cm at [O-2] = 0% to 5.5 x 10(-3) Omega.cm at [O-2] = 100%, and the carrier concentration and the electron mobility substantially decreased. It was also observed that the resistivity slightly decreased by the vacuum annealing but increased by the annealing in pure oxygen. Detailed characterization indicated that concentration of the oxygen vacancy (V-O) donor is reduced and the oxygen interstitial (O-i) acceptors are formed within the samples grown in the O-2-mixed ambient. It was proposed that the electrical properties of the InCdO films may be reasonably explained by the compensation model involving V-O, O-i, In dopants, and/or their acceptor-like complexes.