The anisotropy of Sm 2 Fe 1 7 and Y 2 Fe 1 7 have been measured in order to study individual Sm and Fe sublattice contributions. The effect of Ti substitution for Fe on sublattice anisotropy has been investigated. Both Sm 2 Fe 1 7 - x Ti x and Y 2 Fe 1 7 - x Ti x show planar anisotropy from 78K to T c . No competition occurs between Fe and Sm sublattices, both of which give a negative K 1 constant. Titanium is found to strongly reduce the Sm planar anisotropy while a slight decrease is observed for the Fe contribution. The Ti substitution seems to affect the second order as well as higher crystal field parameters.