As known, mechanical milling is used to prepare alloy powders with a precise compositional control and a notable grain size refinement down to the nanometer-scale. The resultant powders develop through the repeated coldwelding and fracture of the elemental (or pre-alloyed)powders particles by the highly energetic compressive impact forces in the ball mill. Recently, a variety of commercially useful and scientifically interesting materials, such as intermetallics and amorphous, nanocrystalline and nanocomposite materials has been successfully processed. However, the mechanisms of mechanical alloying processes and many related phenomena are still in discussion from a fundamental point of view. Another point unstudied entirely is an effect of milling conditions (especially when using organic liquids as a milling medium) on the mechanochemical process and structure and properties of the powders obtained. In this report our results on studying Fe-based nanostructured powders (Fe-C, Fe-Si, Fe-Si-C, Fe-SiO2) mechanosynthesized in inert Ar+ atmosphere and organic liquids (heptane, oleic acid solution in heptane, water and others) will be presented. Phase composition, structure formation and magnetic properties of the powders synthesized as well as the influence of thermal treatment and surfactant additives on these parameters will be discussed.