Blends of polyethylene (PE) were produced in a single reactor using a combination of {[(2-ArN=C(Me))(2)C5H3N]FeCl2} [Ar=2,6-2CH(3)(C6H4] and rac-Et(Ind)(2)ZrCl2. The experimental results showed that the PEs obtained have a broad molecular weight distribution (MWD) and both the molecular weight and the MWD can be regulated through changing the mole ratio of the two active sites. In addition, the polymerization activities decreased with the increase of the Fe/Zr mole ratio whereas the crystallinity of the PE obtained exhibited a contrary trend, decreasing as the Fe/Zr mole ratio went up. The morphology of the blends also directly relates to the Fe/Zr mole ratio, and more iron content in the bimetallic catalysts system gives rise to compact PEs of high crystallinity. This reflects that the reactor blends are morphology controllable as well and can be easily applied to present processing techniques because of adjustable molecular weights and their distribution. Differential scanning calorimetry, thermogravimetric analysis, gel permeation chromatography, and scanning electron microscopy were employed to characterize the properties of the reactor blends of PEs. (C) 2003 Wiley Periodicals, Inc.