The aim of this work was to investigate the feasibility of a proposed simple bio-oil upgrading technique and test its suitability for bio-oil products. The upgrading technique consisted of vacuum distillation for preliminary water removal, deep water removal, using etylchloride, and catalytic esterification and neutralisation. Two bio-oil samples were produced from slow pyrolysis of sawdust pellets and fast pyrolysis of wheat straw powder. Some activated carbon obtained from slow pyrolysis was the catalyst carrier and p-toluene sulfonic acid was the catalyst. The conditions of the esterification reaction were identified by serious experiments. As a result, the qualities of both bio-oil samples are significantly improved through the upgrade. The heat value of both oils ranged from 14-17 MJ kg(-1) to 25 -29 MJ kg(-1). The final neutralisation step using triethylamine increased the oil pH value close to neutral. The chemical/physical properties of the produced bio-oils were in accordance with the standards for engine fuel. (C) 2013 Elsevier Ltd. All rights reserved.