The effect of particle size on the Br, BHmax, and specific density of Sm(Co0.62Fe0.29Cu0.07Zr0.02)8.0 and Sm(Co0.70Fe0.21Cu0.07Zr0.02)8.0 bonded magnets has been systematically investigated. It was found that magnets made of powders with a top size less than 53 μm have a low specific density and, hence, low Br and BHmax values. Magnets made of powders of about 250 μm top size, with a composition of Sm(Co0.62Fe0.29Cu0.07Zr0.02)8.0, yield a specific density of 7.0 gm/cc (84% of theoretical density), a Br of more than 8.1 kG, and a BHmax of about 15 MGOe. A slight decrease in Br and BHmax was noticed when the particle top size was increased beyond 710 μm. This decrease in Br and BHmax may be attributed to the imperfect grain alignment arising from the fact that each particle may consist of multigrain grains with a random orientation. Because of the slightly lower Fe content, magnets with a composition of S- m(Co0.70Fe0.21Cu0.07Zr0.02)8.0 exhibit slightly lower Br and BHmax values when compared to those of Sm(Co0.62Fe0.29Cu0.07Zr0.02)8.0. However, the relationships of Br and BHmax to particle size are nearly identical for both compositions. When the powder top size was fixed at about 250 μm, a consolidating pressure of 8 T/cm2 appears to be sufficient to obtain magnets with a specific density of 6.9 gm/cc and with a reasonable grain alignment. For Sm(Co0.62Fe0.29Cu0.07Zr0.02)8.0 bonded magnets, a Br of 8.5 kG, Hc of 8.5 kOe, Hci of 23.0 kOe, BHmax of 16.7 MGOe, and Hk of 8.0 kOe were obtained. © 1998 American Institute of Physics.