One-dimensional (1D) magnetic Fe3O4/P(GMA-DVB) peapod-like nanochains have been successfully synthesized by magnetic-field-induced precipitation polymerization using Fe3O4 as building blocks and P(GMA-DVB) as linker. The Fe3O4 microspheres without surface modification can be arranged with the direction of the external magnetic field in a line via the dipolar interaction between Fe3O4 microspheres and linked permanently via P(GMA-DVB) coating during precipitation polymerization. The length of peapod-like nanochains can be controlled by magnetic field intensity, and the thickness of polymer shell can be tuned by the amount of monomers. Magnetic measurement revealed that these 1D peapod-like nanochains showed highly magnetic sensitivity. In the presence of magnetic field, 1D magnetic Fe3O4/P(GMA-DVB) peapod-like nanochains can be oriented and aligned along the direction of external magnetic field. (C) 2012 Elsevier Inc. All rights reserved.