In general, techniques are described for labeling an implantable medical device (IMD). In one example, an IMD can include a housing including electronic circuitry. The IMD can include a header coupled to the housing and includes a core. The core can define a bore and include a first metal label positioned adjacent to the at least one bore. The IMD includes a lead assembly including at least one lead having a distal end and a proximal end, the at least one lead including a second metal label, the distal end including at least one electrode and the proximal end received within the bore.