Interstitial titanium‐chromium oxynitrides in the solid solution series Ti1−zCrz(OxNy) (z= 0.2, 0.4, 0.5, 0.6, 0.8) have been obtained by ammonolysis of the TiO2/Cr2O3 precursors resulting from the coprecipitation method. The precursors and the resulting oxynitrides were characterized by auger electron spectroscopy, X‐ray diffraction analysis, electron probe microanalysis, transmission electron microscopy, and BET surface area techniques. Compounds in the Ti1−zCrz(OxNy) series are prepared as single phases by nitridation at 1073 K for 8 h. The as‐synthesized oxynitride powders contain only Ti1−zCrz(OxNy) with cubic structure and the particle size is in the nanometer scale.