Past and recent seismic events underlined unexpected damage mechanisms of RC-frames consisting of widespread damages and collapses of beam-column joints. These outcomes, mainly concerned RC-frames designed before the introduction of modern seismic codes, clearly emphasize the paramount role of beam-column joints in the context of the seismic safety assessment of RC-frames. In this paper, the Authors present a study devoted to numerically analyze the seismic response of RC-frames obtained by specifically introducing in the typical Finite Element model an additional component interposed between beam and column members able to reproduce the monotonic and cyclic behavior of beam-column joint elements. In particular, the additional component consists of springs arranged according to the scissors model and characterized by constitutive laws calibrated by the Authors in a previous study with reference to different beam-column joint configurations. The numerical simulations carried out with reference to a case study RC frame highlight the importance of considering the role of beam-column joints in the seismic analysis of RC frames.