The paper presents the possibility of creating a new category of magnetic nanocomposite materials, using magnetic nanofluids (MNF) and resins (Crainic et al., 2004). Polymer-embedded nanostructures are potentially useful for a number of technological applications, especially as advanced functional materials (e.g., high-energy radiation shielding materials, microwave absorbers, optical limiters, polarisers, sensors, hydrogen storage systems, etc.) (Carotenuto and Nicolais, 2003; Caseri, 2000; Nicolais and Carotenuto, 2005; Barnet and Peuker, 2006). In addition to the intrinsic nanoscopic material properties and the possibility to make transparent metal-polymer combinations, these materials are interesting also because the presence of a very large filler-matrix interface area can significantly affect the polymer characteristics (e.g., glass transition temperature, crystallinity, free volume content, etc.), allowing the appearance of further technologically exploitable mechanical and physical properties (e.g., fire resistance, low gas diffusivity, etc.) (Nicolais and Carotenuto, 2005).