We present a finite element formulation for simulation of electromechanical coupling using a combination of fictitious domain and level set methods. The electric field is treated with a fixed (Eulerian-like) mesh, whereas the structure (taken as a perfect conductor) is modelled with a conventional Lagrangian approach. The compatibility between the potential of the conductor and of the electric domain is obtained by introducing a Lagrange multiplier function, defined on the boundary of the conductor. The electromechanical forces are obtained using a variational formulation for the coupled electromechanical domain. We use a Heaviside function on the level set to remove the electric energy in the conductor domain. Results are presented for an radio frequency switch and an element of a comb drive. Copyright © 2009 John Wiley & Sons, Ltd.