Using Cowin and Nunziato theory for linear elastic material with voids, some dynamical problems concerning plane wave propagation have been investigated. Apart from the classical longitudinal and transverse waves of classical elasticity, a longitudinal wave corresponding to change in void volume fraction is found to exist in the medium. Using potential method, reflection and transmission of longitudinal and transverse plane waves is studied at a plane interface between two dissimilar elastic solid half-spaces with voids. It is found that the presence of voids in the media affects the reflection/transmission coefficients only for the case of limitly low frequency incident wave. The possibility of propagation of plane waves is investigated by incorporating the micropolarity in the elastic medium with voids. The problem of reflection of longitudinal displacement wave is investigated and it is found that the wave corresponding to change in void volume fraction is significant when the incident wave strikes the free surface normally. The corresponding problem has been extended to rotating micropolar media with voids.