The effects of molecular weight of LNR, as a compatibilizer in NR/LLDPE blends, were studied. Rheological studies and mechanical properties of the blends showed that the molecular weight of LNR played a very important role in determining their performance. The blends that contained 15-25% LNR with an M-u, of 4.8 x 10(5) and an M-n of 1.66 x 10(5) showed the highest mechanical properties. Outside this range of molecular weight, the compatibilizing property of LNR is no longer effective due to inhomogeneous blends. Improvements in the mechanical properties were in consonance with the increase in gel contents of the blends. The additions of LNR in the blends were able to reduce the interfacial tension; therefore, they improved the interaction between the phases of the blends. The studies also confirmed that, within the concentration range investigated, the LNR solvent did not influence the blend properties.