In this work, we present a simple, reproducible and efficient method for the preparation of uniform and compact highly conductive coatings obtained from surfactant-free water-based mixtures of micro-beads made of crosslinked polyurethane (PU) with either carbon black (CB) or multiwall carbon nanotubes (MWNTs). Low percolation thresholds, 2.9 wt.% with CB and 0.8 wt.% with MWNTs, and high saturated conductivities, 200 S/cm for PU/CB and 500 S/cm for PU/MWNT, were achieved. This finding shows that, firstly, highly conductive carbon-based nanocomposite coatings can be made in water without surfactants using N-methylpyrrolidinone (NMP) as dispersing aid, and, secondly, carbon black can be used in place of multiwall carbon nanotubes for making cheaper coatings without sacrificing the electrical performance. (C) 2013 Elsevier B.V. All rights reserved.