Multiwall carbon nanotubes (MWNTs) were synthesized by a novel method of mesoporous MCM-41 and MCM-48 silicates in the absence of any metal traces. A transmission electron microscopy (TEM) study shows that the diameter distribution of the obtained carbon nanotubes is very narrow -5-6 nm in diameter and 200 nm in length - compared to nanotube samples produced by other catalytic chemical vapor deposition (CCVD) techniques. (C) 2002 Elsevier Science B.V. All rights reserved.