This work examines the entrainment of fluid cracking catalyst (FCC) particles from a large bubbling fluidized bed (BFB). An experimental setup consisting of a 0.60-m-inner diameter (i.d.), 5.5-m-high column, a high-efficiency Stairmand cyclone, a sampling valve and a movable conical top was designed and built to measure the entrainment mass rate as well as the size distribution of the FCC particles at several levels along the freeboard. To our knowledge, the size distribution has not previously been reported in the literature. The influence of superficial gas velocities in the range of 0.21 to 0.45 m/s was investigated. The results show that the entrainment rate had an exponential dependence on both freeboard height and superficial gas velocity. The size distribution analysis using dry sieving and a particle analyzer revealed that particle agglomeration occurred only in the dense bed and that neither segregation nor a reduction in particle size due to attrition and/or fragmentation took place. (C) 2014 Elsevier B.V. All rights reserved.