Because composite materials are often used in safety critical applications, such as in aerospace, it is desirable to have a quick and reliable confirmation of their material properties. The aim of this paper is to introduce the idea of inferring elastic and/or viscoelastic material properties from plate wave measurements with a minimum amount of data. Material characterization of anisotropic materials has been a focus point of research for many years. A good review of this literature can be found in a recent review article [1]. Rokhlin and collaborators [2–4] have also studied this problem extensively, using propagation characteristics and the transmission coefficient to reconstruct elastic properties. The advantage of reconstructing the stiffnesses from the zeros of the transmission coefficient lies the the fact that in contrast to the zeros of the reflection coefficient the transmission coefficient zeros are independent of the fluid properties. A drawback of this method is that the plate must be accessible from both sides.