A density functional theory (B3LYP) computational study of the ethylene-styrene copolymerization process using meso-Et(H(4)Ind)(2)Zr(CH3)(2) as the catalyst is presented. The monomer insertion barriers in meso species are evaluated and compared with previously obtained barriers in rac diastereoisomers. Differences related to ethylene homopolymerization and ethylene-styrene copolymerization activities as well as styrene incorporation into the copolymer are found between the meso and rac diastereoisomers. Nevertheless, a migratory insertion mechanism seems to hold for both diastereoisomeric species. (c) 2006 Wiley Periodicals, Inc.