Fe–Co–Nd–Dy–B glassy alloys are a current type of ferromagnetic material. To increase their glass-forming ability against the growth of a crystallization phase, the effects of the addition of transition metals TM (TM=V, Nb, Ta, Cr, Mo, and W) on the glass-formation ability and magnetic properties of Fe62Co9.5Nd3Dy0.5B25 glassy alloy have been investigated. The substitution of 2 at. % elements TM (=Nb, Ta, Mo, and W) for Fe and Co increases crystallization temperature Tx and decreases the onset temperature of solidification Tm, leading to a significant increase in the thermal stability against crystallization for Fe60.3Co9.2TM2Nd3Dy0.5B25. The difference (ΔTx=Tx-Tg) between Tx and the glass transition temperature Tg increases from 55 K at 0 at. % TM to 87 K at 2 at. % TM. The bulk glassy alloy with a diameter up to 1.2 mm was produced by copper mold casting. Also no distinct changes in Tg, Tx and ΔTx are seen for the addition of Cr and V. The results can be explained by the difference of atomic size in the additional elements. The saturation magnetization decreases slightly by the addition of 2 at. % TM elements. The saturation magnetization and coercive force of glassy Fe60.3Co9.2TM2Nd3Dy0.5B25 alloys are 1.13 to 1.19 T and 3.85–4.98 A/m, respectively. © 2002 American Institute of Physics.