The structure, magnetization, and magnetostriction of R(Zn1 xFex)(R = Tb, Dy) polycrystalline alloys were investigated by X-ray diffraction, vibrating sample magnetometry, and standard strain gauge techniques. It was found that TbZn1 xFex consists of a single Tb(Zn,Fe) phase with the cubic CsCl-type structure when x 0 2. DyZn1 xFex was found to consist of nearly a single Dy(Zn,Fe) phase in the range 0 x 0 15. A second Dy-rich phase appears when x 0 15. The Curie temperature of the RZn1 xFex alloys increases with increasing Fe content when x 0 2. When Fe is substituted for Zn in RZn compounds, the magnetization increases with increasing Fe content. The magnetostriction of Tb(Zn1 xFex) alloys increases with increasing Fe content when x 0 1, and that of Dy(Zn1 xFex) alloys increases in the composition range 0 x 0 05.