Abstract In this work, saturated vapor pressures and gaseous pvT properties of a fourth generation refrigerant, trans-1-Chloro-3,3,3-trifluoropropene (R1233zd(E)), were measured using a Burnett apparatus. The vapor pressures were obtained in the temperature range from (288 to 373) K and pressure range from (0.089 to 1.04) MPa. The gaseous pvT properties were obtained in the temperature range from (303 to 373) K, pressure range from (0.091 to 0.99) MPa and density range from (0.038 to 0.40) mol•dm–3. The standard experimental uncertainties were estimated as 4 mK and 0.5 kPa for temperature and pressure, respectively. The relative uncertainty in density is better than 0.1%. A truncated virial equation of state was developed based on the present pvT data.