This paper is devoted to the study of valorization of tar from biomass gasification as a fuel for internal combustion engine. The methods selected were both thermal cracking and catalytic cracking in the presence of zeolite, magnesium oxide, and aluminum oxide catalyst. The chemical composition of the cracking product was analyzed by gas chromatography-mass spectrometry, together with the physico-chemical properties determination (density, viscosity, higher heating value, and acidic value). Thermal cracking of biomass gasification tar gave a yield of bio-diesel 73.67 wt.% of feed. The cracking process in the presence of zeolite, magnesium oxide, and aluminum oxide catalysts gave a yield of biodiesel 62-75 wt.%, 55-66 wt.%, 67-71 wt.% respectively. The influence of the type and quantity of catalyst on production yield and properties of the produced bio-oil is highlighted. The produced bio-oil density and heating value were close to the conventional diesel fuel. The viscosity and acidic value were found to be slightly higher than that of conventional diesel fuel. (C) 2012 Elsevier B.V. All rights reserved.