Co₃O₄ powder was added to barium hexaferrite by powder metallurgy process to determine its effect on the magnetic properties. The variation of the addition of Co₃O₄ are 0.0, 0.5, 1.0, 2.0, 3.0, and 5.0 wt%. Characterization and magnetic testing included density calculation, Permagraph test, and XRD were performed in order to elucidate the effect of Co₃O₄ addition to its structure and magnetic properties of barium hexaferrite. The magnetic density obtained was in the ranges of 3.2 - 4.35 g/cm³. From the permagraph test, it is found that the value of remanence (B_r) was in between 1.18 and 1.5 kG. The value of coercivity (H_c) was in the range of 0.594 - 3.366 kOe, and the maximum product energy (BH_max) was found to be in between 0.07 and 0.48 MGOe. From the XRD analysis, it was found that two types of barium hexaferrite were formed, namely barium hexaferrite type M(BaFe₁₂O₁₉) and X(Ba₂Fe₃₀O₄₆). It is concluded that the addition of the Co₃O₄ compound increased the value of magnetic density and decreased magnetic properties.