Composition for resin-bonded magnets, composed of a magnetic powder and resin binder, the former containing a transition metal element as one of the constituent elements. According to the invention, the binder contains, as the major ingredient, a thermosetting resin containing an organic peroxide and having radical-polymerization reactivity, and is further incorporated with an N-oxyl compound. The subject-matter of the invention extends to a resin-bonded magnet produced by forming said composition by at least one method selected from the group consisting of injection molding, extrusion, injection compression, injection pressing and transfer molding.