In the current work, improvement of the optical properties of Polyaniline (PAni) films was investigated using cold plasma technique. Samples were treated with different gases including argon (Ar), oxygen (O2), nitrogen (N2) and Ar/O2 mixture using low-pressure dc glow discharge. Films of about 300 nm were fabricated by simple deposition of polyaniline suspension in toluene on glass slides. UV-Vis spectrophotometric measurements of the prepared films showed that plasma treatment resulted in a significant increase in the optical band gap of the films. Plasma treatment was found to increase the band gap energies range from (1.7–1.98 eV) of the untreated films to 1.8-2.42 eV of the treated ones. Exposure to oxygen plasma was found to alter the chemical composition of the films and thus, resulting in a high transmission (over 85%) of the peak centred at 550 nm. This increases the photoelectric performance of the plasma treated polyaniline films