Mossbauer and magnetic measurements have been performed on Cr substituted Pb-hexaferrite of composition PbFe 1 2 - x Cr x O 1 9 (0 =< x =< 6). The main hyperfine parameters for the Fe 3 + nuclei of the various sublattices have been determined in the temperature range of 78-800 K. The data obtained give no evidence of deviation of the Fe 3 + magnetic moments from the axial magnetic order. In addition, the Cr 3 + ions do not occupy the hexahedral lattice sites. The rapid fall of the saturation magnetisation with increasing x cannot be simply explained with the replacement of the magnetic moment of the Fe 3 + with that of Cr 3 + . The onset of a complex magnetic order induced by the presence of Cr 3 + ions is involved.