The interest is given on the preparation of nanocomposites of titanium dioxide (TiO2) with conducting polymer polypyrrole (PPy) because the resulting composites possess enhanced photocatalytic activity under visible light in comparison with pure TiO2 photocatalyst. In such composite, there is a synergistic activity of the components. It is very important to optimize the synthesis conditions in order to obtain PPy/TiO2 composites with the optimal thickness of conductive polymer layer on TiO2 and minimal possible aggregation of particles. PPy/TiO2 composites were characterized by Fourier transform infrared spectroscopy, X-ray powder diffraction, UV-Vis spectroscopy, scanning electron microscopy and transmission electron microscopy. The photocatalytic efficiency of the samples was determined by following the decomposition of Reactive Red 45 dye under UV and visible light, which was monitored by UV-Vis spectroscopy (as a change in absorbance of wavelength at 542nm). The results show enhanced photocatalytic efficiency of the samples under visible light.