The oxidation resistance of the ZrB2-HfB2 solid solutions in the temperature range of 1500-1600оС was carried out. The solid solutions have a higher oxidation resistance than individual phases due to the thin oxide layer. The highest oxidation was observed in solid solutions close to HfB2, due to the formation oxide phases with a low diffusion rate of oxygen into the material. The main oxidation mechanism is the reaction of a diboride-based solid solution with oxygen and the formation of an oxide-based solid solutions with saving the Zr/Hf ratio.