We demonstrate the use of dip coating technology as a fabrication tool for highly efficient polymer solar cells. We investigate the critical parameters for dip coating deposition of poly(3-hexylthiophene) (P3HT) and [6,6]-phenyl-C-61-butyric acid methyl ester (PCBM) to obtain optimized active layers. These parameters include the selection of organic solvent, solution concentration and room temperature. Structure and morphology of dip coated films are characterized via X-ray diffraction, UV-visible absorption spectra and atomic force microscopy. We achieve dip coated devices with power conversion efficiency of 3.93%, with fill factor, short circuit current and open circuit voltage of 0.63, 10.62 mA cm(-2) and 0.60 V, respectively, even though the devices were fabricated in air without any annealing treatment. Crown Copyright (C) 2011 Published by Elsevier B.V. All rights reserved.