In this study we report the synthesis of undoped and Sc3+ doped Bi2Fe4O9 nanoparticles using sonochemical technique. X-ray diffraction reveals that all samples are single phase with no impurities detected. EDS analysis was done to confirm the extent of Sc3+ doping in the samples. The size and morphology of the nanoparticles have been analyzed using scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The Bi2Fe4O9 nanoparticles show a weak ferromagnetic behavior at room temperature, which is quite different from the linear M H relationship reported for bulk Bi2Fe4O9. A magnetization of 0.144 mu B/f.u. is obtained at 300 K, which is mainly attributed to the uncompensated moments at the disordered particle surface resulting from the reduced coordination of the surface spins, arising due to lattice strain or oxygen deficiency. Addition of Sc3+ dopant in varying concentrations in these Bi2Fe4O9 nanoparticles, improves their magnetic as well as ferroelectric properties. The leakage current is considerably reduced and electric polarization increases significantly in case of Bi2Fe4(1-x)ScxO9 (x = 0.1) nanoparticles. Thus it can be inferred that Sc3+ doped Bi2Fe4O9 nanoparticles shows promise as good multiferroic materials. (C) 2012 Elsevier B.V. All rights reserved.