The solubility of 1-hexene was measured for linear low-density polyethylenes (LLDPEs) produced over a heterogeneous Ziegler-Natta catalyst, Mg(OEt)(2)/DIBP/TiCl4-TEA (ZN), and over a homogeneous metallocene catalyst, (2-MeInd)(z)ZrCl2-MAO (MT). The 1-hexene solubility in LLDPEs was well represented by the Flory-Huggins equation with a constant value of chi. ZN-LLDPEs dissolved a larger amount of 1-hexene and thus showed a lower value of chi compared to MT-LLDPEs. The Flory-Huggins interaction parameter chi, or the solubility of 1-hexene at a given temperature and pressure, was suggested as a sensitive measure for the composition distribution of LLDPEs.