X-Ray photoelectron spectroscopy (XPS) and electrical resistivity measurements have been performed to investigate the electronic properties of Cr1-xAlxN films. The films, deposited by reactive magnetron sputtering, crystallize in the fee rocksalt type of structure (B1-type) in a wide composition range of 0less than or equal toxless than or equal to0.63. The electrical resistivity was measured from 50 to 320 K. The electrical resistivity at 320 K increases with increasing Al content, and the temperature coefficient of the resistivity is always negative. A detailed study of XPS valence band (VB) spectra shows that the substitution of Cr atoms by Al atoms leads to local modifications of covalent-ionic bonds between N 2p and Cr 3d orbitals. The variations of the VB structure due to the changes in the chemical composition correlate with the electrical and mechanical properties.