Polymer-based nanocomposites have attracted a growing attention in the last few years, as the incorporation of solid nanoparticles into a soft polymeric matrix allows obtaining multi-functional materials with tailored properties, potentially suitable for advanced applications. However, the final properties of the resulting composite systems are strictly dependent on several factors, including the shape and size of the embedded nanoparticles and the interactions taking place between polymer macromolecules and nanofillers (2). In addition, the polymer/nanofillers and nanofillers/nanofillers interactions can significantly affect the viscoelastic properties of polymer-based materials, which have a significant importance from a technological point of view. Furthermore, the study of the rheological response of polymeric nanocomposites can be used as a tool to investigate their microstructure, offering the possibility to gain a fundamental understanding of their structure-properties relationships. In this work, nanostructured composites based on a low molecular weight polyethylene glycol (PEG) and containing hydrotalcite or boehmite nanoparticles have been prepared through melt mixing, aiming at evaluating the effect of the introduction of nanoparticles having different aspect ratios and morphologies on the rheological properties of the polymer matrix. Furthermore, the influence of the temperature on the viscoelastic response of the PEG/modified hydrotalcites nanocomposites was thoroughly investigated.