We investigated theoretically the Cu 2p resonance of 3d, 3p and 3s X-ray photoemission spectra (XPS) in CuO using a cluster model including multiplet coupling, crystal field and anisotropic hybridization. The spectra were calculated by taking into account the radiative transitions up to the first order and Coster-Kronig transitions up to the infinite order. The resonant enhancement is so strong that it can be used to interpret small satellite structures in both core level and valence band photoemission spectra. The influence of the configuration interaction between the 3p(2)3d10 and 3s3d9 final states is discussed.