Deposition of gold on titanium dioxide (TiO 2) nanoparticles is highly beneficial for maximiz-ing the efficiency of many photocatalytic reactions. In this study, we have reported for the first time the use of an electrochemically active biofilm (EAB) for the synthesis of Au@TiO 2 nanocomposite with sodium acetate as the electron donor. The EAB acts as an electron generator for the reduction of gold ions on the surface of TiO 2 nanoparticles. It was observed that the TiO 2 plays not only as a support for the gold nanoparticles but also as a storage of electrons produced by the EAB within the particles. These stored electrons dramatically increase the reduction of gold ions and hence we have observed the formation of the Au@TiO 2 nanocomposites within 90 min. A mechanism of the nanocomposite formation is also proposed. The as-synthesized nanocomposites were characterized by UV–Vis absorption spectroscopy to monitor the proper formation of the nanocomposites. X-ray diffraction and transmission electron micro-scopic analyses were performed to determine the structural and microstructural properties of the nano-composites. High-resolution transmission electron micrographs depict the proper formation of the Au@TiO 2 nanocomposites with gold nanoparticle size varying from 5 to 10 nm with an increase in the gold precursor concentration. Zeta potential measure-ments were used to investigate surface charges of the as-synthesized nanocomposites. This novel biogenic route represents a unique pathway for the low cost, eco-friendly, rapid, and controlled synthesis of nano-structured Au@TiO 2 hybrid systems which will truly revolutionize the synthetic fields of nanocomposites.