In this article, partial molar volumes of hydrophobic compounds in water were reviewed. Distorted surfaces of the partial molar volumes for alkylbenzenes in water were drawn in a wide range of pressure, 0.10–400 MPa, and temperature, 273–323 K. They include a domain of negative compressibility of the partial molar volume in a low temperature and low pressure region. The negative compressibility was ascribed to a well‐known property of bulk water; more compressible at lower temperature in the observed region. Aromatic ring which was included in naphthalene, anthracene, etc. contribute to the positive sign of the volume change for hydrophobic hydration though the negative sign has been usually observed for a methylene group of many hydrophobic compounds. © 2004 American Institute of Physics