A method is presented to determine the elastic constants for an isotropic, porous, elastic solid saturated by a two-phase fluid. Assuming that the shear modulus of the empty matrix is known, it is shown that the six additional coefficients in the stress-strain relations can be uniquely determined by performing two ideal experiments referred to as “generalized jacketed and partially jacketed compressibility tests,” in analogy with the single-phase theory of Biot. Under reasonable assumptions on the behavior of the material, the experiments yield expressions for the coefficients in terms of the material properties of the individual phases and the capillary pressure function relating the pressures in the two fluid phases. Finally, numerical results showing properties of the phase velocities and attenuations for the four different types of body waves are presented and analyzed. © 1990, Acoustical Society of America. All rights reserved.