AbstractThis paper reports on the technical implementation and the successful commissioning of the beam current feedback regulation system of the RF neutral beam sources for ASDEX Upgrade. The beam current is regulated by adjusting the RF input power. This is possible due to the fast response of the beam current to changes of the RF input power within a few milliseconds. With beam current feedback regulation, perveanced-matched operation of the sources can be maintained throughout the pulse, thereby increasing the beam quality and the source reliability.