The temperature behavior of bismuth orthoferrite nanoparticles obtained by the glycine-nitrate combustion method was studied by high-temperature X-ray diffractometry and complex thermal analysis. The region of stability of the material in a single-phase state was found. It was shown that the nanocrystalline BiFeO ₃ did not undergo decay in the temperature interval 550–780 °С. In this temperature interval, we have obtained the nanocrystalline material with average crystallite sizes 40–90 nm and average particle sizes 100–150 nm the sizes of which depend on temperature. The features of formation of BiFeO ₃ and the process of their sintering were studied. Results show that the crystallite growth slowed down after the amorphous phase disappeared. The sintering of nanopowder became more intense in the temperature interval 600–700 °С, but no noticeable increase in the crystallite sizes occurred. The magnetic behavior of obtained material was also discussed. It was found to be consistent with the concept of violation of the cycloidal magnetic order in bismuth orthoferrite.