Mixtures of difluoromethane (HFC-32) and 1,1,1,2,3,3,3-heptafluoropropane (HFC-227ea) are promising alternative refrigerants; however, there is currently no available published experimental PVTx data. The gaseous PVTx properties of HFC-32 (1) + HFC-227ea (2) mixtures were measured using the Burnett-isochoric method with 251 data sets obtained for temperatures from (310 to 410) K, pressures up to 3658 kPa, and densities up to 206 kg center dot m(-3) at x(1) = 0.2648, x(1) = 0.5155, and x(1) = 0.7809. The temperature, pressure, and mole fraction uncertainties were estimated to be +/- 10 mK, +/- 100 Pa, and +/- 0.01 %, respectively. A truncated virial equation was used to correlate the experimental data, with the second and third virial coefficients for the binary mixtures also determined.