The presence of an FCC catalyst solves the problems related to the thermal cracking of vegetable oils and animal fats. FCC catalysts are very effective in removing oxygen from biomass by transformation into CO2, CO and water without using hydrogen and allowing the control of the final product distribution. Thus, as mentioned above, the FCC unit of a refinery seems to be the most appropriate system for the co-processing of this renewable raw material. Moreover, physical properties of triglyceride-based feedstocks are close to those found in typical refining streams that are usually fed to the FCC unit (H/C mass ratio, density, viscosity. . .) as well as the fact of the high miscibility. Co-processing of triglyceride-based biomass in the FCC unit not only would help to achieve the bio-component target fixed by the EU directive (Commission Directive 2009/28/ EC) but also to the improvement of some properties in the final FCC products. Processing these renewable materials in a refinery would lead to a lower content in metals (such as nickel or vanadium) and heteroatoms (such as sulphur or nitrogen) in the final products due to the fact that this feedstock does not contain those metals and heteroatoms in their composition. Moreover, they are formed by paraffinic and olefinic hydrocarbons, more crackable than the aromatic compounds present in the typical streams usually fed to the FCC unit, which tend to remain as unaltered compounds in the low-value heaviest fractions. Other benefits would be a slight increase in the coke production, which could help to maintain the thermal balance between the reactor and the regenerator in the FCC unit; higher olefin production in the gas fraction, which favours the application of these compounds to produce polymers, alkylates and tertiary ethers; and an increase in the amount of gasoline and in its octane number due to enhancement of aromatization reactions and olefins production.