The present study provides a multi-scale investigation of the crystalline quality and the structural defects present in heteroepitaxial diamond films grown on iridium/SrTiO3 (001) substrates bymicrowave plasma assisted chemical vapor deposition. X-ray diffraction, Raman spectroscopy and low temperature cathodoluminescence are combined to accurately characterize the mosaicity, the density of dislocations and the residual strain within the films. X-ray diffraction and Raman results confirm a structural quality at the state-of-the-art according to the epitaxial relationship 〈100〉diamond(001) // 〈100〉iridium(001) // 〈100〉SrTiO3 (001). In addition, Raman and cathodoluminescence observations on cross-sections reveal the presence of local strain.