The nature of dark matter is one of the great mysteries of modern physics. Its existence has been inferred from its gravitational effects over many distance scalesi, but currently no known particle can account for the observed data. As a result new particles beyond the standard model have been suggested. The axion is one such particle that was originally devised as a solution to the strong-CP problem in nuclear physics (or the peculiar absence of a measurable electric dipole moment in the neutron). The Axion Dark Matter eXperiment (ADMX), and its sister experiment ADMX-High Frequency (ADMX-HF), are designed to detect axions by using large microwave cavities immersed in a strong magnetic field to resonantly convert the axion’s rest mass into detectable photons. In this talk I will describe the history of axion searches and the ADMX experiment in particular, which ran at LLNL for over a decade before being moved to the University of Washington. I will then discuss the upgrades to the ADMX experiment as it prepares for it’s upcoming search with orders of magnitude greater sensitivity. I will also outline R&D efforts that are currently being undertaken to expand the search range of ADMX further and ultimately determine if axions are, or are not, the major dark matter component of the Universe.