The structure and magnetic properties of Nd8.4Fe86Mo1.1B4.5 nanostructured magnets prepared by mechanical alloying (MA), compared with those by mechanical milling (MM), were studied. The intrinsic coercivity μ0Hc, the reduced remanence Jr/Js, and the maximum magnetic energy product (BH)max for Nd8.4Fe86Mo1.1B4.5 magnets were prepared by MM were notably higher than the values of the corresponding MA-prepared samples. The average grain sizes of both α–Fe and Nd2Fe14B in the MM-prepared samples were measurably smaller than corresponding values of the MA-prepared samples. A more homogeneous distribution of α–Fe grains in the MM-prepared samples than in the MA-prepared samples was obtained.