The magnetic properties and structures of (Sm,Zr) 5 (Fe,Co) 17¹x Ti x (x = 02.0) melt-spun ribbons were investigated in the as-quenched condition and after annealing. The as-quenched (Sm,Zr) 5 (Fe,Co) 17¹x Ti x (x = 00.5) specimens consisted of the Sm 5 Fe 17-type and SmFe 3-type phases, while the as-quenched (Sm,Zr) 5 (Fe,Co) 17¹x Ti x (x = 1.02.0) specimens contained the SmFe 3-type phase. These specimens showed low coercivity regardless of the Ti content. Heat treatment of the melt-spun ribbons resulted in a drastic increase in coercivity. The maximum coercivity of 1.11 MAm ¹1 was achieved in the (Sm,Zr) 5 (Fe,Co) 15.5 Ti 1.5 specimen annealed at 1073 K. Microstructural studies revealed that the annealed specimen consisted mainly of the SmFe 3-type phase. The achieved high coercivity of the annealed specimen was therefore attributed to the existence of the SmFe 3-type phase.