Glycerol reforming was investigated under supercritical water conditions (450-575 degrees C, 250 bar). A feed containing 5 wt.% of glycerol was continuously fed to an empty Inconel 625 reactor. The products of the reaction were separated into gas and liquid phases in a condenser. At a feed rate of 2.15 g/min, the glycerol conversion significantly increased from 0.05 to 0.97 when increasing operating temperature from 450 to 575 degrees C. Although lowering the feed rate (i.e. increasing the residence time) could considerably improve the conversion, carbon formation became a problem especially at high operating temperatures (550 -575 degrees C). The major gaseous products were hydrogen (approximately 60 mol%), carbon monoxide, carbon dioxide and methane with some traces of ethane, ethylene, propane, and propylene. Various liquid products were detected including acetaldehyde, acetol, methanol, acetic acid, propionaldehyde, allyl alcohol, acetone, acrolein, ethanol, ethylene glycol, and acrylic acid but the major liquid components were acetaldehyde and acetol. With a feed glycerol concentration of 2.5 wt.% and operating temperature of 525 degrees C, glycerol conversion of 0.91 and H-2 yield of 2.86 can be obtained without carbon formation. Finally, it was demonstrated that higher H2 yield with much lower carbon formation was observed in supercritical water reforming (250 bar) compared to conventional steam reforming at 1 bar under similar temperatures. Copyright (C) 2013, Hydrogen Energy Publications, LLC. Published by Elsevier Ltd. All rights reserved.