High pressure and high temperature density data for the mixtures methyl nonafluorobutyl ether (HFE-7100) + n-heptane are reported in this work, at pressures from 0.1 to 80 MPa and temperatures from 298.15 to 393.15 K. The uncertainty of experimental measurements is 0.7 kg.m(-3), performed by means of a vibrating tube densitometer. The Tait-like equation was used to fit the experimental density data, with low standard deviations. Moreover, the derived properties isobaric thermal expansivity and isothermal compressibility were calculated.