Abstract: A process for the production of a sodium-filled valve in which the sodium is introduced into a hollow valve stem through a filling bore of relatively large diameter and which is sealed through a plug and/or usual welding. Subsequent to the closing off of the filling bore, the hollow inner space is evacuated through a passageway having a small cross-section and is thereafter sealed vacuum-tightly in a vacuum through either welding or soldering. Through the evacuation of the hollow space there is avoided any kind of oxydation of the sodium and thereby any change. Moreover, no froth or foam formation is encountered so as to facilitate the presence of an extremely constant heat transfer.