Thin films of polypyrrole doped by polyanions have been deposited onto stainless steel and carbon fibers by anodic electropolymerization of pyrrole in the presence of an anionic polyelectrolyte in water. Films with a thickness smaller than 600 nm have been formed, which strongly adhere to the solid supports. The polymeric dopant has been selected for its ability to complex silver ions. Scanning electron microscopy, Rutherford backscattering analyses, and IR spectroscopy have confirmed that silver is actually immobilized in the films and provides them with an antibacterial activity against the Gram-negative bacteria Escherichia coli and Gram-positive bacteria Staphylococcus aureus.