The response modification factor (R) plays a vital role in the non-linear response of a structure, hence in the seismic design of a structure. While designing a structure, an engineer can follow linear elastic force based design method, using this factor in the design; accounts for the non-linear behavior. The study focuses on estimating the actual values of this factor for RC special moment resisting frames. The paper emphasizes on the variation of the factor by performing detailed non-linear static pushover analysis of 2D framed structures of special moment resisting frames. A parametric study has been carried out considering the variation of time period of the structure and zone factor. From the detailed analysis, a relationship between Rμ-T-Z has been proposed. The results show that the values of R, given in the codes are over-estimated; hence, a realistic value shall be adopted based on the analytical results. As an application, the values arrived from the proposed relationship is then compared with the values obtained from the structures analyzed. © 2015 Research India Publications.