The present invention refer to a innovative process for obtaining nanoparticulate magnetic ferrites, at low temperatures, simple or mixed, functionalized by organic molecules, for dispersion of these nanoparticles in polar or nonpolar media, and the same particles dispersed in a liquid medium, also known as ferrofluids. The present invention enables obtaining both simple ferrites (MFe2O4 or MFe12O19) and mixed ferrites (Nx M(1−x)Fe2O4 or N1−Y Mx+Y Fe(2−x)O4; as example) where M and N can be metals, such as Sm, La, Bi, Ba, Mo, Sr, Ni, Fe, Mn, Cr, etc., through the coprecipitation method, functionalized by organic molecules containing carboxylic groups, which are polymers, or long chain acids or short chain acids, containing mono, di or tricarboxylic groups and/or alcohols, whose dispersion in polar or nonpolar media is improved. The present invention enables also obtaining ferrofluids, through the mixture of the obtained magnetic particles with an appropriate liquid carrier. The substitution of some elements in the ferrites may yield specific mechanical, optical and/or magnetic properties.