Composites of water-soluble conducting polyaniline copolymers, poly(aniline-co-aminobenzenesulfonic acid) (PAOABSA), containing gamma-Fe(2)O(3)magnetic particles with nanometer size, were synthesized by a chemical method. The ferromagnetic properties of the resulting PAOABSA composites were measured as a function of the pH value of the reaction solution, the sulfonated degree of the copolymer, and the concentration of FeCl2. The structure of the composites was characterized by means of elemental analysis, FTIR, XPS, and X-ray diffraction. It was found that increasing the pH value of the reaction solution and the concentration of FeCl2 is favorable for an enhancement of the saturated magnetization. As high as 33.2 emu/g of saturated magnetization for the PAOABSA composites was observed. No hysteresis loop (i.e. H-c = 0) was observed, which is independent of the preparation conditions. Structure characterizations show that iron oxide existing in the composite is mainly gamma-Fe2O3, which is responsible for the ferromagnetic properties of the PAOABSA composites, whereas gamma-Fe2O3 magnetic particles nanometer in size (similar to 85 nm) may be attributed to a lower coercive force (i.e. H-c = 0) of the composites.