A near‐infrared reflectivity exceeding 60% at 2.5‐&mgr;m wavelength has been observed for a polycrystalline, rf sputter‐deposited electrochromic (EC) WO3film in a deeply colored state. This reflectivity is considerably higher than that previously reported for a thermally evaporated EC‐WO3film that was crystallized by a post‐deposition thermal anneal. The shapes of the x‐ray spectra of the two films are also different. The results of ellipsometry measurements of the optical constants provide convincing evidence for the validity of a free‐electron Drude model to explain the reflectivity modulation observed in polycrystalline EC‐WO3.