Carbon nanotubes grown on clay platelets (Clay-CNTs hybrids) were incorporated into a poly(l-lactide) (PLLA) matrix through high energy ball milling at ambient temperature. Carbon content was varied from 0.60 to 5 wt%. Crude carbon nanotubes (CNTs), after purification from the clay, were also incorporated into PLLA in the same conditions and amount. Thin films were obtained on laboratory scale. Electrical behaviour was analysed on all nanocomposites. CNTs grown on the clay platelets showed a better dispersion into the polymer matrix than the crude ones, as evidenced in a significant decreasing of percolation threshold. I–V characteristics were also dependent on the morphology of the filler.