A new amorphous semiconductor, 2CdO⋅PbOx(band gap: 1.58 eV), was found. Thin films of this material were prepared by rf sputtering of a Cd2PbO4target in O2–Ar. The dc conductivity of the resulting amorphous thin films was ∼180 S cm−1at 300 K and remained almost constant down to ∼4 K. The concentration of carrier electrons and the Hall mobility in the as‐deposited state were 1×1020cm−3and 9 cm2 V−1 s−1, respectively. When the as‐deposited specimens were heated to 250 °C, which is far below the crystallization (to Cd2PbO4) temperature (460 °C), the conductivity and the carrier concentration at 300 K became approximately twice as high. The thermal O2‐desorption measurements demonstrated that carrier electrons are generated via the formation of oxygen vacancies at the initial stage (<250 °C) of thermal desorption of O2from the amorphous structure. The effective mass of carrier electrons was estimated as 0.57m0. ©1996 American Institute of Physics.