In this paper we studied the possibility of synthesizing solid solutions based on barium hexaferrite, iron atoms Fe3+ in which are partially substituted by Cr3+ atoms, and their magnetic properties. Thirteen solid solutions of BaFe12-xCrxO19 compositions with varying degrees of chromium substitution x (Cr) = 0–6 with a step of x (Cr) = 0.5 were obtained using the solid-phase synthesis method. X-ray phase analysis showed that at a temperature of T = 1400 °C, solid solutions with a single crystalline phase corresponding to the structure of magnetoplumbite were formed within 5 h. As a result of chromium Cr3+substitution for iron Fe3+, a monotonous decrease in the parameters of the crystal lattice occurred. We studied the temperature and frequency dependences of the initial magnetic permeability of the resulting ferrites. It was revealed that substitution of iron by chromium led to a decrease in the Curie temperature. All the studied compositions had a feature in the form of a narrow peak near the Curie temperature. We suggested that this feature appeared as a result of a change in the domain structure. Analysis of the temperature dependences allowed us to conclude that Cr3+ substituted for iron in all crystallographic positions with equal probability. It was shown that the initial permeability of ferrites decreased with increasing frequency.