The morphology and electrical properties of linear low density polyethylene (LLDPE)/poly (ethylenemethyl arylate) (EMA) blends filled with carbon black (CB) are investigated in this work. Comparing to LLDPE/CB composite, the higher percolation threshold of EMA/CB composite is attributed to the good interaction between EMA and CB. However, carbon black is found to locate preferentially in the LLDPE phase of LLDPE/EMA immiscible blends from the characterization of SEM and electrical properties, which greatly decreases the percolation threshold of the composites. The viscosity of the two polymers is the key factor to determine the distribution of CB instead of interfacial energy in this system. This suggests a method to control the distribution of CB in the immiscible blends by choosing the viscosity ratio of polymer blend. (c) 2006 Wiley Periodicals, Inc. J Appl Polym Sci 103: 487492,2007