Soil modified with Expanded Polystyrene beads results in lightweight mixtures used in many geotechnical applications. Investigating the dynamic behavior of such mixture may enhance its applications. This paper presents a laboratory characterization program using sand mixed with EPS particulates. The host sand was modified with up to 2.5% EPS beads by weight, which corresponds to approximately 70% EPS by volume. The paper focuses on the small strain dynamic properties of these composite mixtures at increasing percentages of beads and different confining pressures using Resonant Column tests. Results indicate that for each 0.5% increase in the beads content there is an average reduction of 12% in dry unit weight. The small strain dynamic properties show decreased shear stiffness with increasing EPS beads content and less influenced material damping with increasing the beads content. Overall, the laboratory evaluation of these sand-EPS bead mixtures resulted in properties that are within the range of engineering use and could be considered as an alternative construction material in various geotechnical applications.