Upgrading of pyrolysis oil from biomass offers great potential economic and environmental benefits for the production of sustainable and renewable energy sources. Meanwhile, challenges remain in the development of technical- and cost-effective catalysts and operating processes. One promising approach is liquid phase upgrading, which exhibits numerous benefits. This paper reviews recent progress and future possibilities for obtaining fuels from biomass using this approach. Key upgrading reactions for different oxygenated compounds in pyrolysis oil, including ketonization, aldol condensation, alkylation, hydrodeoxygenation, and oxygenation are discussed. Development of effective catalysts and efficient integration of multiple consecutive reaction steps in one single reactor make liquid phase upgrading competitively advantageous. (C) 2013 Elsevier B.V. All rights reserved.