A numerical model for the nonlinear analysis of infilled RC frames based on the finite element method is presented. The infill panel material nonlinearities due to cracking and crushing are considered using ANSYS® Program. An extensive survey of published work on general concepts of infilled frames under cyclic loading is presented. Numerical parametric studies have been conducted to investigate different factors affecting the behavior of reinforced concrete infilled frames under cyclic loading. A rational approach for equivalent diagonal strut is developed which can help in the design of reinforced concrete infilled frames.