Two types of inorganic supports, MgCl 2 and SiO 2 , for the impregnation of catalysts were prepared by the recrystallization and the sol-gel method, respectively. The polyethylene produced by the Ziegler-Natta/metallocene hybrid and mixed catalysts showed two melting temperatures and a bimodal MWD corresponding to products arising from each of the individual catalysts. This suggests that these Ziegler-Natta/metallocene catalysts acted as individual active species, and as a result, produced a blend of polymers.