Kinetic data related to complex mixtures of reactants and catalysts are necessary to simulate design and rate industrial chemical reactors. In the particular case of Fluidised-bed Catalytic Cracking, the main reaction takes place in riser reactors; whereas laboratory data are obtained in small fixed bed reactors. Even though this important difference in size and hydrodynamics, laboratory reactors are used to estimate, accurately, yield to products and apparent activation energies of the reactions proposed; however estimated frequency factors are very different from the ones observed at industrial reactors. In this work a scaling-up of frequency factors is performed, assuming that activation energies estimated in laboratory are correct. The adjusting effort is minimised because it is necessary to scale-up only one of the reaction rates and the rest of them are fitted proportionally to the first one. A 5-lump kinetic scheme for catalytic cracking of vacuum gas oils is used to test this approach; prediction obtained for industrial yields is very accurate. (C) 2006 Elsevier Ltd. All rights reserved.