Experiments in a pilot-scale fluidized-bed reactor have been carried out to investigate the carbonation reaction of CaO, as a potential method for CO2 capture from combustion flue gases at high-temperatures. Results show that CO2 capture efficiencies are very high, while there is a sufficient fraction of CaO in the bed reacting in the fast reaction regime. The total capture capacity of the bed decays with the number of carbonation-calcination cycles. The experimental CO2 concentration profiles measured inside the bed during the fast reaction period are interpreted with the KL fluid bed model, by supplying information on. sorbent deactivation from laboratory tests. It is concluded that a fluidized bed of CaO can be a suitable reactor to achieve very effective CO2 capture efficiencies from a combustion flue gas. (C) 2004 American Institute of Chemical Engineers AIChE J, 50: 1614 -1622, 2004