Cloud point isopleths were measured for a binary system of linear low density polyethylene (LLDPE) and ethylene. Cloud points were determined at temperatures between 395 and 440 K and pressures up to 175 MPa. The LLDPE used was made from hydrogenated polybutadiene and was almost monodisperse (M-w/M-n = 1.08). The experimental data were modelled with the Sanchez-Lacombe equation of state. The parameters for LLDPE were found by performing a sequence of non-linear regressions on both the experimental cloud-point data and pressure-volume-temperature reference data for molten polyethylene. The Sanchez-Lacombe equation fits the data well, although not within the experimental uncertainty. (C) 2002 Elsevier Science B.V. All rights reserved.