The response of a bi-layer conducting polymer-based actuator has been studied with respect to various parameters such as backing layer thickness, backing layer modulus, applied voltage, etc. The bending angles for the bi-layer actuators made by depositing, conducting polypyrrole (PPy) films on backing layers using LDPE/LLDPE, SBS, Hytrel, PP, PET materials have been compared. The response of the bi-layer actuators indicates that there is optimum for the backing layer thickness as well as its material modulus together with the thickness of the conducting polymer at which the maximum bending is observed. Other geometrical parameters such as a length to width ratio also influence the response of these actuators and have to be chosen properly for the best actuator performance. © 2005 Elsevier B.V. All rights reserved.