The effect of applied processing history and postprocessing annealing treatment on the rheological properties has been studied for a binary blend composed of linear low-density polyethylene (LLDPE) and low-density polyethylene produced by radical polymerization (LDPE). It has been found that intensive processing in an internal mixer depresses oscillatory modulus, especially storage modulus, at lower frequency region for LDPE and the blends with LLDPE, whereas the rheological properties of LLDPE are independent of both processing and annealing procedures. Further, the depression of the modulus is found to be more prominent for the blends with 20-40 wt % of LLDPE than that for the pure LDPE, although the phenomenon is ascribed to conformation change of long-chain branches. Moreover, the blends show slower recovery of the modulus during the postprocessing annealing than do LDPE. The results demonstrate that processing and mixing conditions have to be considered seriously for LDPE/LLDPE blends showing enhanced melt elasticity. (c) 2006 Wiley Periodicals, Inc.