Graphene is a material with surprising properties, that very recently aroused the attention of the scientific world for its potential application in different fields from electronics to sensors. To date, many works have been already published dealt with graphene-based sensor in which the preparation of the devices involved the use of some lithographic method. It is known, however, that typical nano-lithographic processes leave an uncontrolled residue on graphene. In this work we present a graphene based chemiresistor, where the electrode structure is realized by Ion Beam Induced Deposition technique; the current-voltage characteristics of such a device will be investigated in different environments. (C) 2010 Published by Elsevier Ltd.