Different kinds of silver nanostructures have been deposited on the surface of the polypyrrole (PPy) films by silver-mirror reaction. The morphology of silver nanostructures can be controlled by modulating the reaction conditions. The application of the as-prepared PPy-silver composites in surface-enhanced Raman scattering (SERS) was studied using 4-mercaptopyridine (4-Mpy) as probe molecules. The results showed that PPy-silver composites exhibited excellence SERS ability and could be used as SERS-active substrates for detection of trace molecules. (C) 2010 Elsevier B.V. All rights reserved.