Density data of the dimethyl carbonate + decane system are reported from T = 283.15 to 328.15 K and p = 0.1 to 40 MPa over the whole composition range. An automated measuring device, based on the vibrating tube principle, is used. Data are correlated through a temperature-dependent Tait equation that allows us to derive isothermal compressibilities and isobaric thermal expansivities. Excess quantities for molar volume, isothermal compressibility, and isobaric thermal expansivity are also given.