The partial molar volume and the solvation free energy of five globular proteins in aqueous solutions are calculated by the three-dimensional reference interaction site model theory, a modern integral equation theory of molecular liquids. The partial molar volume calculated by the theory shows quantitative agreement with the corresponding experimental data. Concerning the solvation free energy, the theoretical results are compared with estimations by an empirical method which uses the accessible surface area of atoms, because the corresponding experimental data are not available. Possible applications of the method to problems related to the solvation thermodynamics of protein are discussed. (C) 2004 Elsevier B.V. All rights reserved.