The PVT properties of dinitrogen monoxide (N2O) have been measured. In particular, experiments were performed by means of two different apparatus, both in the two-phase region and in the superheated vapor-phase region:  the isochoric method was applied in the saturation region, and the Burnett method was applied in the vapor region. Isochoric measurements were carried out at temperatures from (219 to 273) K and at pressures from (550 to 3100) kPa. The 18 measurements along the saturated liquid−vapor region were fit, together with selected literature data, with the Wagner equation. For Burnett measurements, 14 runs along 7 isotherms in a pressure range from (170 to 5200) kPa were made. The second and third virial coefficients were derived, and good consistency was found after comparison with data in the literature.