We have investigated the flame synthesis of carbon nanotubes (CNTs) using a wall stagnation flow burner, in which a rich ethylene/air premixed gas diluted by nitrogen was used as a reactant gas. A trumpet-shaped flame was formed only on the boundary between the reactant flow and the atmospheric air, so that the wall surface was exposed to the unburned reactant gas. Multi-walled CNTs with tidily parallel and straight layers were synthesized on the stagnation wall, which was covered by Ni metal. This flame synthesis technique is very unique, and it may have potential for utilization in mass production. (C) 2004 Elsevier B.V. All rights reserved.