Mechanical alloying of the elemental powder mixture of iron and multiwalled carbon nanotubes (10, 20 and 30 vol.%) was performed in a high energy planetary ball mill. Nanocomposite materials obtained were examined by X-ray diffraction method as well as by transmission and scanning electron microscopy. It is shown that several phases were forming at the different stages of the milling process, namely, alpha-(Fe,C) and gamma-(Fe,C) supersaturated solid solutions along with the Fe3-xC and the Fe7C3 carbide phases. The hardness and magnetic properties (Curie temperature and coercive force) of the nanocomposite materials obtained were studied. The process of the mechanical alloying of materials studied has been analyzed. (C) 2017 The Society of Powder Technology Japan. Published by Elsevier B.V. and The Society of Powder Technology Japan. All rights reserved.