Volumetric properties of systems, i.e., volume (density) along with other related quantities, excess volume, isobaric expansivity, isothermal compressibility, isentropic compressibility, and speed of sound, are required for the development of equations of state of systems. The knowledge of the state behavior combined with thermal properties enables the calculation of non-measurable thermodynamic properties on the basis of classical thermodynamics. While thermal properties are related to derivatives of ther- dynamic functions with respect to temperature, the volumetric properties determine changes of ther- dynamic functions with pressure. Volumetric properties of pure liquids and liquid mixtures and solutions are important from the theoretical point of view because they reflect the structure and the intermolecular interactions in the system. Accurate volumetric data are needed for converting the volume-based quantities into mass or amou- of-substance based quantities. From the chemicalengineering point of view the knowledge of volumetric properties is indispensable in all material balances required for the design of technological processes, storage and transportation of products. The present volume is a compilation of volumetric property data on subcritical binary homogeneous (single-phase) or heterogeneous (two-phase) liquid–liquid mixtures. All the components are well-defined pure substances, which are organic or inorganic nonelectrolytes, including low-melting ionic liquids and water. Only data obtained by, or derived from, direct experimental measurements are considered.