Abstract <p>The incidence of a deformation harmonic wave on the boundary of a porous and fractured-porous medium has been studied. The study was carried out within the framework of a two-velocity model of a porous medium and a three-velocity model of a fractured-porous medium. The cases of saturation of media with liquid or gas have been considered. At the boundary of the media, the pores are considered to be open. The dependencies of complex reflection and transmission coefficients of harmonic waves on the frequency of oscillations and on the incident angle have been calculated. It has been established that the main reflected and transmitted waves are deformation and transverse waves, and the amplitudes of the filtration waves that arise during reflection and transmission are small.</p>