A simple three-dimensional soil-structure interaction (SSI) model is proposed. First, a model is developed for a layered soil medium. In that model, the layered soil medium is divided into thin layers and each thin layer is represented by a parametric model. The parameters of this model are determined, in terms of the thickness and elastic properties of the sublayer, by matching, in frequency-wave number space, the actual dynamic stiffness matrices of the sublayer when the sublayer is thin and subjected to plane strain and out-of-plane deformations with those predicted by the parametric model developed in this study. Then, by adding the structure to soil model a three-dimensional finite element model is established for the soil-structure system. For the floors and footings of the structure, rigid diaphragm model is employed. Based on the proposed model, a general computer software is developed. Though the model accommodates both the static and dynamic interaction effects, the program is developed presently for static case only and will be extended to dynamic case in a future study. To assess the proposed SSI model, the model is applied to four examples, which are chosen to be static so that they can be analyzed by the developed program. The results are compared with those obtained by other methods. It is found that the proposed model can be used reliably in SSI analysis, and accommodates not only the interaction between soil and structure; but, also the interaction between footings. (C) 2000 Elsevier Science Inc. All rights reserved.