Transparent and conductive single-walled carbon nanotube (SWNT) thin films were fabricated onto glass substrates and their optical and electrical properties were evaluated. Particular attention was given to the dependence of the conductivity and optical transparency on the thickness of the films. Furthermore, the SWNT thin films were integrated in organic photovoltaic devices as the hole transport electrode. The best photovoltaic performance was observed for the devices utilizing 80 nm SWNT films with a sheet resistance of 362 Omega/sq, and a transmittance of 64% at 520 nm. The experiments reveal that SWNTs films can be used as transparent electrodes for efficient, flexible organic photovoltaic devices. (c) 2007 Elsevier B.V. All rights reserved.