Nitrogen-doped tin oxide (SnO2:N) thin films were deposited on flexible polyethylene terephthalate (PET) substrates at room temperature by RF-magnetron sputtering. Effects of oxygen partial pressure (0-4%) on electrical and optical properties of thin films were investigated. Experimental results showed that SnO2:N films were amorphous state, and O/Sn ratios of SnO2:N films were deviated from the standard stoichiometry 2:1. Optical band gap of SnO2:N films increased from approximately 3.10 eV to 3.42 eV as oxygen partial pressure increased from 0% to 4%. For SnO2:N thin films deposited on PET, transmittance was about 80% in the visible light region. The best transparent conductive oxide (TCO) deposited on flexible PET substrates was SnO2:N thin films preparing at 2% oxygen partial pressure, the transmittance was about 80% and electrical conductivity was about 9.1 x 10(-4) Omega cm. (C) 2015 Elsevier Ltd. All rights reserved.