Group of carbon nanstructures discovered since the first observations of fullerenes and carbon nanotubes, are regarded as materials of future generation. Fullerenes, carbon nanotubes and graphene are probably the most known representatives of the recently discovered group of carbon allotropes. In order to increase practical application, aforementioned carbon nanostructures are commonly introduced in a variety of matrix materials, particularly polymers. Efficiency of carbon nanofillers in tailoring electromagnetic, electrical, mechanical, thermal and other properties of polymer materials according to the customer’s needs is largely dependent on the structural pecularities of the nanofiller itself (chirality, anisometry, dimensions, presence of functional groups etc) as well as interplay of the ingredients of the composites in micro- and nanolevels. Consequently in the current research attention is focused to the investigation of the shape (isometric carbon onions, anisometric carbon nanotubes, plate-like graphene) of the structure and dielectric properties of thermoplastic polymers based composites. The efficiency of carbon nanofillers distribution in the polymer matrix has been modified by means of non- covalent and covalent methods (surfactant addition and nanofiller surface functionalization, respectively). Broadband dielectric spectrometry (DES), differential scanning calorimetry (DSC), dynamic mechanical thermal analysis (DMTA), X-ray diffraction analysis (XRD) and Z-potential analysis have been used to characterize structure and dielectric properties of the investigated nanocomposites.