WO3/carbon nanotube (CNT) catalysts with different WO3 loadings were prepared by wet impregnation with ammonium paratungstate as precursor, characterized by X-ray diffraction, temperature-programmed reduction, transmission electron microscopy and X-ray photoemission spectroscopy. These materials were tested for C-6 olefin skeletal isomerization in different activation (pre-reduction) conditions and compared to a reference tungstated zirconia, WO3/ZrO2, catalyst. They led to very high skeletal isomerization selectivities at 200 degrees C at high conversion level without any observable deactivation. (c) 2005 Elsevier B.V. All rights reserved.