Two FCC catalysts with a 60 mum average size, prepared with different crystallite sizes (0.4 and 0.9 mum), are studied in terms of total acidity, energy of ammonia desorption, specific surface area, relative amount of Bronsted and Lewis acid sites, crystallite and particle size, and micropore size distribution. Characterization of these catalysts is relevant in view of their application to test the extent of intracrystallite diffusive transport influence on the overall catalytic cracking rates as developed, in separate studies [Ind. Eng. Chem. Res. 42 (2003) 4162] in a novel CREC Riser Simulator. (C) 2004 Elsevier B.V. All rights reserved.