CrN and CrN layers of 130-250 nm thickness were deposited onto silicon substrates via reactive magnetron sputtering. Their oxidation at 500-800-degrees-C in air was studied via depth profiling nuclear methods. The Cr and N concentration profiles were determined by Rutherford backscattering spectrometry and resonant nuclear reaction analysis, respectively. In the case of oxidizing Cr2N, the nitrogen content behind the Cr2O3/Cr2N interface increases to the stoichiometry of CrN. At a Cr2O3 layer thickness of about half the as-deposited Cr2N layer. the oxidation rate is reduced to that of CrN.