In this study, the effect of solvent swelling on conversion of organic carbon in kerogen isolated from Goynuk (Turkey) oil shale into volatile hydrocarbons, polycyclic aromatic hydrocarbons (asphaltenes and preasphaltenes) and carbon in solid residue was investigated. Kerogen was isolated by successive HCl. HNO3, and HF treatments. isolated kerogen samples were swollen by hydrogen bonding solvents Such as DMSO, pyridine and THF. The extent of weight loss Caused by kerogen structural changes because of solvent swelling was evaluated by using analysis data. The values of rate of decomposition demonstrated that the temperature range for decomposition changed and rate of decomposition increased due to solvent swelling. A series of temperature-programmed pyrolysis operations were performed with kerogen of Goynuk oil shale, and swollen kerogens samples in DMSO, Pyridine and THF. The pyrolysis results indicated that the solvent swelling enhanced partially the conversion of kerogen in pyrolysis processing. (C) 2008 Elsevier B.V. All rights reserved.