CoNi electrodeposition in the presence of barium ferrite nanoparticles has been performed in a bath containing a cationic surfactant, in order to prepare magnetic composites. Magnetic particles did not significantly influence the metallic deposition process. The application of a magnetic field during the electrodeposition over silicon-base substrates has been also analysed. The application of a magnet attached to the silicon/seed-layer substrate inhibited the onset of the deposition process as a consequence of the hindrance of the cathode by the magnetic particles surrounding the electrode. However, once the deposition process begins, the applied magnetic field clearly favours the nanoparticles incorporation by modulating the deposition potential or current density. Barium ferrite percentage of the deposits increased at low current densities or deposition potentials. (C) 2007 Elsevier B.V. All rights reserved.