Key model bio-oil O-compounds representing some of the major oxygenate groups, such as acetic acid, hydroxyacetone and phenol, were mixed with a standard gasoil and tested under fluid catalytic cracking (FCC) conditions in a laboratory-scale unit using an industrial FCC equilibrium catalyst (E-CAT) and a mixture of E-CAT and ZSM-5 additive. As a general trend, acetic acid, phenol or hydroxyacetone when mixed with a conventional gasoil increased the overall conversion, defined as fraction of the feed converted into gases, gasoline and coke, reduced the coke yield and increased fuel gas, LPG and gasoline. The conversion of the gasoil itself over pure E-CAT was not altered significantly by the presence of these compounds. This result could be interpreted by a preferential adsorption of the feed on the catalytic surface instead of the oxygen containing compounds. On the other hand, the ZSM-5 additive effect was attenuated in the presence of the O-compounds, suggesting a preferential interaction of such compounds with the ZSM-5. Up to 10 wt.% of these O-compounds studied can be processed without major problems in a FCC unit except for phenol. (C) 2009 Elsevier B.V. All rights reserved.