In the present study, the optical and electrical properties of Polymethylmethacrylate (PMMA) films have been investigated under the effect of direct current (DC) glow discharge plasma. PMMA films have been prepared and treated with low-pressure DC glow discharge plasma at different plasma conditions; mainly various working gas and plasma treatment times. The optical and electrical properties of the treated PMMA samples were measured and compared to the untreated one. Nitrogen, argon, and nitrogen-argon mixture have been used as working gases. Plasma parameters, such as the electron density, the ion density, and electron temperature, were measured, at the position of the PMMA films, using Langmuir probe. The results reveal that, the optical properties of PMMA were found to be more sensitive to N 2-plasma treatment than Ar and N 2-Ar gas mixture. The optical energy gap showed a decreasing behavior with increasing the treatment time of N 2 plasma, however, the band tail width and the electrical resistivity increased