The methylaluminoxane (MAO)/SiO2 in situ- and ex situ-supported Et(Ind)(2)ZrC](2) catalysts were prepared and studied for ethylene/1-olefin (1-hexene, 1-octene, and 1-decene) copolymerization for linear low-density polyethylene (LLDPE) production. The in situ-supported catalytic system exhibited higher activities than the ex situ-supported catalytic system. Activities continuously increased as the [Al]((MAO))/[Zr] molar ratio increased up to 1135. The optimum [Al]((TMA))/[Zr] molar ratio was 2500. The ethylene/1-octene (EO) copolymerization showed the most consistency, in regard to activity, for both catalytic systems. The copolymers produced in both systems were random copolymers.