Oxacillin, a semisynthetic penicillinase-resistant penicillin, was incorporated as a dopant within polypyrrole. The oxacillin-doped polymer was deposited at gold, platinum and the biocompatible substrate, titanium. A doping level of 0.12 was obtained during the early stages of polymer formation. Smooth polymer films were deposited, but more structure was observed in the cross sections of the polymer. This was attributed to a reduction in the concentration of the anionic oxacillin as the interfacial pH decreased due to the electropolymerisation reaction, shifting the equilibrium in favour of the undissociated oxacillin, HOx. Although HOx has poor solubility and may precipitate at the polymer solution interface during formation of the polymer, there was no evidence of any reduction in the conducting properties of the polymer. High charging capacitance values of 12 to 15 mF cm−2 were estimated for the oxidised polymer. These conducting properties were attributed to a slow rate of electropolymerisation that prevented significant acidification at the electrode interface, preventing the build-up of HOx. The oxacillin-doped polypyrrole showed cation exchange properties. Oxacillin was maintained within the polymer, as the polymer was cycled between its oxidised and reduced states to give an immobilised antibiotic with very little oxacillin detected in the solution phase. The application of a layer of chitosan gave rise to a slight reduction in the charging capacitance of PPyOx. However, improved adhesion was observed for the reduced PPyOx with the application of the chitosan layer.