One hundred and fifty eight pressure-volume-temperature data points for 1,1,1,3,3,3-hetafuoropropane (HFC-236fa) in the gaseous phase were measured using Burnett-isochoric methods. Burnett expansion measurements were made at both 373.15 and 383-15 K. The pressure-density relationships established at 383.15 K were used as a basis to collect data along 10 isochores for temperatures from 298.15 to 393.15 K for pressures up to 2.3 MPa. The temperature and pressure uncertainties were estimated to be +/-10 mK and +/-300 Pa respectively. The second and third virial coefficients were determined along 17 isotherms with a truncated virial EOS developed using the present data to represent the gaseous thermodynamic properties of HFC-236fa. The acoustic data derived from the present virial EOS are in excellent agreement with those reported by Gillis, with maximum and RMS deviations of 0.045 and 0.016%. Some vapor pressure data were also obtained and compared with literature data. (C) 2004 Elsevier B.V. All rights reserved.