Magnetic submicron particles of MnFe2O4, NiFe2O4 or CoFe2O4 were created in or around the porous sulfonated beads based on poly(styrene-co-divinylbenzene)using an in situ inorganic precipitation procedure. The copolymer beads were treated with a mixed iron/cobalt chloride electrolyte and the doped copolymer networks were converted to their oxides by reaction with sodium hydroxide and potassium nitrate in aqueous solution. Energy dispersive X-ray spectroscopy (EDS) coupled to scanning electron microscopy (SEM) allowed the observation of the presence of submicron particles in the 0.1-0.5 mu m size range, which chemical microanalysis of emitted X-rays revealed the presence of metal oxide particle, such as nickel, manganese or cobalt iron oxide. The morphological features of the binary material particles have depended on the ferrite type. All beads have presented dispersed and agglomerated submicron particles of ferrite located on their surface and inner part as well. Magnetization data of the microbeads showed good ferromagnetic behavior. (c) 2005 Elsevier Ltd. All rights reserved.