A number of experimental studies have been reported in recent literature about the beneficial effects of infill walls on the seismic response of reinforced concrete (RC) frames. Recent large interest in nonlinear seismic analysis methods, static and dynamic, has required proper strategies of behavior based on reliable, and at the same time easy to use, constitutive laws for the Structural elements; however, most of the proposed numerical works develop sophisticated three-dimensional solid models under monotonic load. In this paper, firstly, detailed presentation of simplified two-dimensional discrete finite element model that has been constructed for reinforced-concrete frames with/without masonry infill under monotonic and cyclic loading. Element types and steel cyclic constitutive models were described. The interactions between infillwall and concrete were accurately modeled to simulate the actual behavior of RC infilled frame. Both material and geometrical nonlinearities were considered. Secondly, experimental program and results are presented and discussed on single-storey, single-bay, 1/2-scaled infilled RC frames subjected to lateral cyclic loading to verify the models. The suggested finite element models showed good agreement with experimental results (lateral load and failure mode).a comparison between monotonic and cyclic model showed that no difference in the two models in case of bare frame, but there is a significant difference in case of infilled frame. The test results showed a significant increase in the yield and ultimate strength capacities of the infilled frame with a decrease in relative story drifts. The energy dissipation capacities of the infilled frame turned out to be more than those of the bare infilled frame, thus reducing the seismic demand imposed on the frames