The present study describes the preparation and characterization of poly(N-pyrrole phosphonic acid)-Fe3O4 (PPP/Fe3O4-NPs) nanocomposite. Structural characterizations and some physical properties such as magnetism, ac-dc conductivity performance and dielectric permittivity of the nanocomposite were performed by FT-IR. XRD, TGA, TEM and VSM (vibrating sample magnetometer). FT-IR measurements of the nanocomposite showed that the Fe3O4-NPs bound to the polymer chains via phosphonic acid moieties. From the XRD powder pattern, the crystallite size was estimated as 11 +/- 4 nm which is consistent with the TEM micrographs and magnetic core size from VSM measurements. Analysis of conductivity and permittivity meausurements revealed the magnetic transition above 60 which gives rise to the maximum conductivity of 1.7 x 10(-6) S cm(-1) at 100 degrees C. (C) 2011 Elsevier B.V. All rights reserved.