The effect of small concentration of methylene blue on the photocurrents were studied in solid-state photoelectrochemical cells fabricated using conducting polypyrrole (PPy) coated electrodes sandwiched with solid polymer electrolyte viz. polyvinyl alcohol (PVA) with phosphoric acid. These exhibit excellent photo-response to visible light: photocurrent being 3 to 4 orders of magnitude greater than dark current depending on the concentration of the sensitizer. The current-voltage characteristics in such cells reveal that the charge transport is mainly governed by the space charge effects and the sensitization effects are due to lowering of potential barrier formed at the PPy/PVA interface under photoexcitation. © 1998 Elsevier Science B.V. All rights reserved.