A polypyrrole/polyvinylphosphate (PPy/PVP) polymer was prepared electrochemically from aqueous solutions of pyrrole and polyvinylphosphate. The polymer was found to have a ratio of 10:1 for nitrogen to phosphorous, a water content of 28 ± 3%, and a conductivity of 0.28 S cm-1. The polymer, as shown by SEM and AFM, has a rough amorphous morphology. Electrochemical studies using electrodes with thin polymer films indicated that oxidation/reduction of the material varied depending on whether potassium, sodium, calcium, lithium, magnesium or hydrogen phosphate ion was present. Transport of each of these ions across membranes composed of the above polymer was achieved using pulsed potential waveforms. © 1999 Elsevier Science S.A. All rights reserved.