The electronic structure of IrO2 has been investigated using hard X-ray photoelectron spectroscopy (HAXPES) and density functional theory (DFT). Excellent agreement is observed between theory and experiment. We show that the electronic structure of IrO2 involves crystal field splitting of the iridium 5d orbitals in a distorted octahedral field. The behaviour of IrO2 closely follows the theoretical predictions of Goodenough for conductive rutile-structured oxides. 1 Strong satellites associated with the core lines are ascribed to final state screening effects. A simple plasmon model for the satellites applicable to many other metallic oxides appears to be not valid for IrO2.