a b s t r a c tThe purpose of this study is to evaluate the dynamic mechanical properties of syntactic foam core sandwich structures. Aluminum matrix syntactic foams with carbon fabric skins are studied. Syntactic foams incorporate porosity in their foam-like structure by means of hollow particles. The material examined here is composed of a core made of aluminum A356 matrix filled with alumina hollow particles. Two types of sandwich composites are studied containing: (a) a single layer of carbon fabric and (b) three layers of the same fabric in 0 /90 orientation. Dynamic characterization was conducted using a free vibration method to determine the resonant frequency of the sandwich beams. The dynamic modulus, storage modulus, loss modulus and damping ratio were calculated from the test results. The experimental results were used to validate the predictions of a theoretical model. The experimental values for Young's modulus of one-and three-layer fabric sandwiches were measured to be 32.57 ± 2.15 and 37.33 ± 1.12 GPa, respectively. The experimental results are in close agreement with the theoretical model.