Liquid densities have been measured with a variable volume cell for propane + linear low-density polyethylene systems. The temperature and pressure ranges studied are (354-378)K and (4.00-7.00) MPa, and polyethylene mass fractions in the mixtures vary between 0 and 0.0355. Altogether, 107 liquid density data points are reported. The results obtained for pure propane agree well with literature values. Results show that densities increase almost linearly with increasing mass fraction of the polymer.