The search for more efficient concrete structures requires use of new materials in the developed of new concretes. With this objective, it was proposed in this study the substitution of Part of the medium sand of the lightweight structural concrete for expanded polystyrene (PS). It was replaced 5%, 10% and 20% of the sand to observe the changes in compressive strength, flowability, absorption, density and modulus of elasticity of these concretes. The results of the study show that there was an increase in the absorption and loss in the compressive strength and modulus of elasticity. Also, there was a significant increase in the flowability and reduction in the density of these concretes. Even with the replacement of part of the medium sand by expanded polystyrene, the concretes developed were classified as lightweight structural concretes, showing the applicability of this substitution in concrete designs.