The pyrolysis reactions of soybean oils have been Studied. The pyrolytic products were analyzed by GC-MS and FTIR and show the formation of olefins, paraffins, carboxylic acids and aldehydes. Several kinds of catalysts were compared. It was found that the amounts of carboxylic acids and aldehydes were significantly decreased by using base catalysts such as Na(2)CO(3) and K(2)CO(3). The low acid Value pyrolytic products showed good cold flow properties and good solubility in diesel oil at low temperature. The results presented ill this work have shown that the pyrolysis of soybean oils generates fuels that have chemical composition similar to petroleum based fuels. Crown Copyright (C) 2009 Published by Elsevier Ltd. All rights reserved.