Nylon 11 samples were filled with conducting polymer, polyaniline (PANI) of two different concentration (1% and 5% w/w) each. The samples in the form of disc containing above concentration were obtained by hot press molding. The structural properties have been investigated using density measurements, wide angle X-ray diffraction (WAXD) and Fourier transform infrared spectroscopy (FTIR) techniques. The morphology of pure and filled samples has been studied using scanning electron microscopy. Glass transition (Tg) temperature was determined using dynamic mechanical thermal analyzer (DMTA). The result shows that there is slight crystal modification due to addition of fillers and this effect reduced the crystallinity marginally. (C) 2007 Elsevier B.V. All rights reserved.