Transition metal oxides have attracted increasing interest in recent years, mainly because they are promising materials for applications in memory chip technology (MRAM). Regarding their use in applications their thermal stability and chemical inertness are important advantages. However, there is a lack of understanding of their physical and chemical properties, partly due to their complex nature. This study aims to fill this knowledge gap by determining the electronic and geometric structure of thin CoO films on Au(111) and Ag(100) substrates. From the various preparation methods for transition metal oxides the evaporation of metallic Co in an O2 atmosphere was chosen, since this method proved to yield NiO films of bulk like properties on Ag(100) and Au(111). In general, Ag and Au are supposed to be suitable substrates for CoO, because the lattice mismatch between their lattice and that of CoO is small enough (ca. 4%), to enable epitaxial growth with a 1:1 relation of the lattices. Auger electron diffraction (AED) is a well-suited method to probe the epitaxial relation and the atomic structure of such films. The experimental AED results were compared with simulated data, which showed that the CoO films grew in the rocksalt structure with the orientation of the Au(111) and Ag(100) substrates. Concerning the electronic structure of CoO, the theoretical description is still a matter of discussion, mainly due to the importance of the correlation of the Co 3d-electrons. Another difficulty is the mixing of Co and O states in the valence band region. In both of the theoretical approaches (local density approximation band structure calculations or ab-initio cluster calculations) it is difficult to take all of these aspects into account appropriately. In order to address this topic experimentally and extend the experimental basis, investigations with angle-resolved UV photoemission spectroscopy (ARUPS) have been performed. The resonance behaviour of the photoemission lines in the valence band region was investigated by constant-initial state spectroscopy (CIS). The dispersion of the transitions was found to be similar to previous results on a single-crystal CoO(100) surface.