Plasma polymerized o-methoxyaniline (PPOMA) thin films of different thicknesses were prepared in glow discharge plasma using a parallel plate capacitively coupled polymerization reactor. The PPOMA thin films are smooth, flawless and pinhole free. Fourier transform infrared spectra reveal a decrease of absorption intensity and disappearance of some absorption peaks for PPOMA as compared to those of OMA, indicating the formation of the thin film with modified/changed chemical structure. Analyses of the ultraviolet-visible spectroscopic results reveal that the allowed indirect (Egi) and direct (Egd) band gap energies have values in the range 1.68 to 2.08 eV and 2.90 to 3.08 eV, respectively for PPOMA thin films of thicknesses from 100 to 300 nm. The Egi of the experimental PPOMA thin films does not show any definite trend with film thickness, whereas the Egd shows weak dependence on film thickness. (C) 2013 Elsevier B. V. All rights reserved.