The machine design, power supply, and machine protection, as well as the different heating systems installed at ASDEX Upgrade are discussed. The available auxiliary heating power of 30 MW, supplied by three different heating systems, allows the power deposition to be varied and species heated over a large range. These three heating systems - neutral beam, ion cyclotron, and electron cyclotron heating - are presented in detail. A description of the pellet refueling system is included, which is successfully used for density control.