TiO2 incorporation into an isotactic polypropylene (iPP) polymeric matrix was achieved via a straightforward and cost-effective melting process using laboratory-made nanometric anatase-TiO2 and an industrial polymer. The structural characteristics of the resulting nanocomposite thin films as a function of the inorganic component content were examined using wide and small angle X-ray scattering (WAXS/SAXS) and vibrational Raman spectroscopy. Electron scanning and transmission microscopy (SEM/TEM) studies were also performed to provide evidence of the nanometric dispersion of the oxide within the polymer matrix, showing the presence of average aggregates of ca. 80 nm. TiO2 incorporation into the iPP renders self-sterilized nanocomposite films upon light excitation, the activity of which was tested against Gram negative (P. aeruginosa) and positive (E. faecalis) bacteria. TiO2 displays maximum activity for a sample containing a 2 wt.% of anatase-TiO2 irrespective of the microorganism nature. The antimicrobial activity of the nanocomposite films is significantly enhanced with respect to that of the oxide alone. This key fact is interpreted on physical basis with the help of a complete optical (UV-vis and photoluminescence) and electron paramagnetic resonance (EPR) characterization. (C) 2009 Elsevier B.V. All rights reserved.