From the viewpoint of electronic and telecommunication devices, the electrical resistivity is required to be high to curb the eddy current losses for efficient performance at high frequencies. In the present work, Sro.5Bao.5Fe]2019 hexaferrite has been doped with a binary mixture of lanthanurn and nickel u. chemical co-precipitation method of synthesis. The crystallite size of the synthesized samples is estimated in the range of 36-58 nm and their structural analyses have confirmed a single magnetoplumbite ph The magnitude of the dc-electrical resistivity is enhanced, by almost 100 times, but Curie temperature (Tc) is reduced by doping with La-Ni, which has been explained on the basis of the exchange interaction. In addition, the doped samples exhibit very low dielectric constant (t = 11 -13) and low dielectric tangent (tan 3 = 0.07-0.10) determined at a frequency of I MHz. These characteristics may be suitable for their potential application in electromagnetic attenuation materials and microwave devices. 0 2009 Elsevier B.V. All rights reserved.