A method (10) of forming an electrically conducting feedthrough. The method (10) comprises a first step (11) of forming an electrically conductive structure (21) comprising a sacrificial component and a non-sacrificial component. At least a portion of the non-sacrificial component can then be coated with a relatively electrically insulating material (35) prior to removal of at least a portion of the sacrificial component from the electrically conductive structure. The structure of the feedthrough provides electrical connection through the wall of a housing of an implantable component while preventing unwanted transfer of materials between the interior of the component and the surrounding environment.