A simple, low cost and continuous growth method for the production of well graphitized multi-wall carbon nanotubes is described. The growth takes place in an AC arc in water between two carbon electrodes. At a voltage of 40 V the arc is stable in the range of 85-45 A, lower current values help in increasing the fraction of carbon nanotubes in the product. (C) 2003 Elsevier Science B.V. All rights reserved.