Аннотация:Crystal field in hydrogenated and nitrogenated SmFe 11Ti compound was discussed. The aim of the work was to study the effect of interstitial hydrogen on the rare-earth crystal field in SmFe 11TiH single crystal, based on single ion anisotropy model and to compare it with the effect of interstitial nitrogen atoms on the SmFe 11TiN. Results showed that the effects of the hydrogen and the nitrogen atoms on the rare earth sublattice anisotropy are opposite.