As the lowest cost biomass-derived liquids, pyrolysis oils (also called bio-oils) represent a promising vector for biomass to fuels conversion. However, bio-oils require upgrading to interface with existing infrastructure. A potential pathway for producing fuels from pyrolysis oils proceeds through gasification, the conversion to synthesis gas. In this work, the conversion of bio-oils to syngas via catalytic partial oxidation over Rh-Ce is evaluated using two reactor configurations. In one instance, pyrolysis oils are oxidized in excess steam in a freeboard and passed over the catalyst in a second zone. In the second instance, bio-oils are introduced directly to the catalyst. Coke formation is avoided in both configurations due to rapid oxidation. H(2) and CO can be produced autothermally over Rh-Cc catalysts with millisecond contact times. Co-processing of bio-oil with methane or methanol improved the reactor operation stability. (C) 2010 Professor T. Nejat Veziroglu. Published by Elsevier Ltd. All rights reserved.