In this study, undoped polyaniline-poly(methyl methacrylate) films were cast from solutions containing different amounts of soluble part of undoped polyaniline and poly(methyl methacrylate) in dimethylformamide. The films contained undoped polyaniline up to 60% since the solubility of undoped polyaniline in dimethylformamide was 1.14 g/100 mL. The conductivity of undoped polyaniline-poly(methyl methacrylate) films were investigated after being redoped in some acids such as oxalic, nitric, and hydrochloric acids. When the films doped with hydrochloric acid was kept in air, the conductivity decreased gradually by 32%. Their temperature sensor behavior was examined in the range of -15 to 120 degreesC. The characterization of films was performed by conductivity measurement, FT-IR, UV, and TGA techniques.