Mn-doped BiFeO3 (BiFe1-xMnxO3 x - 0, 0.05, 0.1) nanoparticles were synthesized by hydrothermal method. X-ray diffraction (XRD) and transmission electron microscopy (TEM) studies indicate that the particle size decreases when doped with Mn. The ferroelectric Curie temperature estimated from differential thermal analysis (DTA) study shows a decreasing tendency with the increase of Mn concentration. Magnetic study shows that below 200 K all samples exhibit ferromagnetic behavior and magnetization value at 10 K increases from 0.0027 to 2.75 emu/gm when doped with 5% Mn. Enhancement of magnetization observed in these nanocrystals were discussed on the basis of the combined effect of local ferrimagnetization by B-site doping and the breakdown of spin cycloid due to smaller particle size. (C) 2011 Published by Elsevier B.V.