In this communication, we present the fabrication and the characterisation of micro-heating elements made on polyimide (PI) sheets and on spin coated polyimide membranes. Different types of polyimide and heater materials were investigated to realise micro-hotplates for gas-sensing and thermal actuating applications. The effects of the type of polyimide used and of the different annealing performed on the mechanical and electrical properties of the metallic heaters were characterised. Using an optimised combination of materials and processes, flexible micro-hotplates on polyimide sheets and on polyimide membranes on silicon were realised and their thermal properties evaluated. Platinum and aluminium micro-heating elements on polyimide exhibited promising characteristics for their integration in low-power gas sensors and thermal actuators. © 2006 Elsevier B.V. All rights reserved.