Transparent, flexible and conductive thin films of reduced graphene oxide or different types of carbon nanotubes have been prepared through the liquid-liquid interfacial method, and deposited over two different substrates, glass or polyethylene terephthalate (PET). Sheet resistance, morphology, transmittance and electrochemical measurements of the films have been evaluated in order to verify potential application as transparent electrodes. The effect of the amount of carbon nanostructures on the properties of the films, as well as the effect of the annealing treatment at different temperatures, has been also evaluated. Results shown that all films can be successfully used as electrodes, presenting optimized sheet resistances ranging from 1.7 to 50 k Omega/square and transmittances at 550 nm up to 85 %. Flexible and transparent electrodes presenting high stability have been obtained by the carbon nanostructure films deposited over PET. A modification of the electrodes has been demonstrated, through an electropolymerization of aniline, confirming the potential for further application as flexible devices. (C) 2015 Published by Elsevier Ltd.