The copolymerization of styrene and ethylene was attempted in the presence of the catalytic system CpTiCl3-methylaluminoxane. Polymerizations were carried out at different polymerization temperatures and Al Ti mole ratios. The structure of the polymer was investigated with FTIR, DSC, GPC, and 13C-NMR techniques. The polymerization product was composed of polyethylene and syndiotactic polystyrene. No ethylene-styrene copolymer was detected. The composition of the product was dependent on the polymerization conditions. The catalyst activity was highest at polymerization temperature 30 °C and Al Ti ratio 1500. Styrene concentration of the product was highest at polymerization temperature 50 °C and Al Ti ratio 1500. The melting temperature of the polyethylene fraction was dependent on the styrene content of the product, suggesting some interaction between the monomers in the polymerization reaction. The formation of separate polymer fractions may indicate a different polymerization mechanism for the two monomers, or the presence of more than one active species in the catalyst, one producing polyethylene and the other syndiotactic polystyrene.