This work reports an original method for synthesis of well-crystallized manganese ferrite (MnFe2O4) nanoparticles via a high energy wet milling technique under atmospheric conditions, starting from metallic Mn and Fe powders in the presence of distilled water. The effects of milling conditions on the formation and magnetic properties of MnFe2O4 nanoparticles were investigated in detail. Fully stoichiometric MnFe2O4 nanocrystals with an average crystallite size of 14.5 nm were produced after 24 h of milling. As-synthesized MnFe2O4 nanocrystals were found to show soft magnetic behavior at room temperature with saturation magnetization of 53 emu/g. Due to reduced thermal effects, the saturation magnetization increased to 68 emu/g at 5 K. Results show that this method is simple and efficient for the mass production of MnFe2O4 nanoparticles. (C) 2014 Elsevier Ltd and Techna Group S.r.l. All rights reserved.