Abstract: The magnetization curves of the Y2(FexCo1 –x)17 compounds were measured in the temperature range of 300–923 K along easy and hard magnetization directions. The magnetization curves were analyzed, and the magnetocrystalline anisotropy constants K1, 2 of the samples were calculated. The temperature and composition dependences of the anisotropy constants K1, 2 and the saturation magnetization Ms were discussed. It was shown that, with increasing relative iron concentration in the samples, the first anisotropy constant K1 increases and reaches a maximum value of 5.1 × 105 J m–3 at x = 0.29. © Pleiades Publishing, Ltd. 2024. ISSN 1062-8738, Bulletin of the Russian Academy of Sciences: Physics, 2024, Vol. 88, No. 5, pp. 793–797. Pleiades Publishing, Ltd., 2024.