In an implantable medical device and a method for assembly thereof, a hermetically sealed housing encloses electronic circuitry and has a housing fastener part that is formed of metal and that protrudes from the housing. A per-fabricated header, for receiving conducting leads and for connecting the conducting leads to the electronic circuitry, has a header fastener part also formed of metal. The header is fastened to the housing by metal-to-metal welding of the housing fastener part and the header fastener part at a distance from the housing.
