Critical properties of binary mixtures of 1,2,2,2-tetrafluoroethyl trifluoromethyl ether (HFE-227me) with two hydrofluoroethers, trifluoromethoxymethane (HFE-143m) and methyl pentafluoroethyl ether (HFE-245mc), were measured. The uncertainties were +/- 10 mK in temperature, +/- 0.5 kPa in pressure, and +/- 1.0 kg.m(-3) in density. The experimental data were correlated with equations proposed by Higashi.