Experiments have demonstrated the reforming of hydrocarbons in supercritical water. The hydrocarbons were reformed in a continuously operated tubular V4A reactor. The influences of four different commercial steam reforming catalysts were analysed. The experimental results showed that n-decane can be converted to a hydrogen-rich gas. Furthermore, experiments with diesel oil showed the possibility of fuel conversion at low temperature with commercial steam reforming catalysts. Low temperatures and the use of catalysts lead to inhibition of coke formation during the process. The supercritical reforming offers the possibility of a new low temperature hydrocarbon conversion process to hydrogen for fuel cell applications. (C) 2004 Elsevier B.V. All rights reserved.