The effect of p-type doping by spontaneous reduction using Ag and Ni on electrical properties of single-walled carbon nanotube (SWCNT) transparent conductive films was investigated. The Ag- and Ni-doped SWCNT films have a transmittance of 86.9-88.4% at 550 nm and a sheet resistance of 226-513 Omega/sq in a range of the concentration from 10 to 200 mM. Using Raman and UV-vis-NIR spectroscopy, it was observed that the electrical structure of SWCNTs is changed by p-type doping. So, Ag and Ni could be used as effective p-type dopants to improve electrical properties of SWCNT films. (C) 2012 Elsevier B. V. All rights reserved.