Structural integrity and seismic protection of the buildings against earthquake have been challenging among structural engineers. Many studies have been devoted to development of seismic isolators to improve the seismic behavior of civil structures. This study presents the analysis of building structures with SAP2000 considering soil structure interaction and base isolation effects under El Centro. Four different models are analyzed including fixed base structure, base isolated structure, frame supported by spring representing the soil and structure with combined base isolation and spring. The seismic results are investigated in terms of displacement, shear force, axial force, moment and drift of the columns and beams. It was observed that the soil structure interaction provides some flexibility to the structure by increasing the displacements of the structure and imposing internal forces variation to the system. Therefore, modeling base isolation together with consideration of soil structure interaction leads to better prediction of structural response.