Different ferrites (CoFe2O4, ZnFe2O4, MnFe2O4) and magnetite were synthesized from corresponding salts exclusively inside poly(styrenesulfonate)/poly(allylamine hydrochloride) polyelectrolyte capsules of 10 mum diameter. Polyelectrolyte capsules with synthesized ferrite (magnetite) particles possess enough magnetic activity to be easily manipulated in water solution by an external magnetic field. These composites were characterized by TEM, SEM, and WAXS techniques. The influence of the initial concentration of inorganic salts and inner capsule composition on the characteristics of the resulting inorganic precipitates was investigated.