The reinforced concrete rigid frame constitutes one of the typical lateral resisting systems to lateral forces of buildings in the Middle East zones. The structure of the frame system is based on an empty system (free of infilled hollow blocks). Even if engineers do not take infilled RC frames into consideration in their structural analysis and design, they contribute significantly in the seismic resisting behavior of a building. Researchers said that filling frames with light weight concrete blocks may play a bracing role to the whole structure, it also increases the over-all stiffness of the building in the case of a good construction practice. The objective of this study is to investigate numerically the seismic behavior of infilled reinforced concrete frame. To achieve this goal, a nonlinear inelastic finite element model, using ABAQUS software, is developed. Then the validity of the proposed model is proved through comparison of its results with those of the experiment carried out in Stanford University . In addition, the effect of masonry infill on the performance of RC-frame subjected to simultaneous action of constant vertical load is investigated. The results are examined with respect to ultimate strength, drift ratio, and mode of failure. At last, recommendations are proposed for an adequate evaluation on the seismic response of the infilled frames.