The results of a comparative analysis performed on specimens of nanostructured epoxy resins obtained by different boehmite filler concentrations are reported in this paper. The specimens were prepared by dispersion of boehmite nanoparticles into a cycloaliphatic epoxy resin cross linked under UV. Photopolymerization process was followed by RT-FTIR and the properties of uv-cured films investigated. Dielectric properties, in particular space charge accumulation, are measured as a function of nanofiller content. Results indicate that space charge build up and charge mobility are affected largely by filler content. Concentrations of nanofiller of 5-7 wt % show significant decrease of the space charge with respect to the base-epoxy resin and an increased mobility of negative carriers. (C) 2009 Wiley Periodicals, Inc. I Appl Polym Sci 114:2541-2546,2009