A new magnetically responsive three-component nanocomposite consisting of CoFe2O4, polyaniline (PANI) and nanosilver has been prepared by coating of CoFe2O4 nanoparticles with PANI and subsequent immobilization of silver nanoparticles onto the surface of the polyaniline shell. The as-prepared CoFe2O4/PANI/Ag nanocomposite has been characterized by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), field emission scanning electron microscopy (FESEM), transmission electron microscopy (TEM), and vibrating sample magnetometer (VSM). Inlaying the pre-synthesized CoFe2O4/PANI composite with silver nanoparticles enhances its electrical conductivity as well as its catalytic and antibacterial activities. The CoFe2O4/PANI/Ag nanocomposite shows good antibacterial activity against some Gram-positive and Gram-negative bacteria. Although the saturation magnetization of the CoFe2O4 core decreases significantly on coating with PANI and nanosilver shells, the CoFe2O4/PANI/Ag nanocomposite can be still separated from water solution through magnetic decantation.