Two types of inorganic supports, MgCl2 and SiO2, 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. (C) 2000 Elsevier Science B.V. All rights reserved.