Evaluation of the degrees of structural damage suffered by high-rise residential buildings after being subjected to strong ground motions is extremely important to the development of life continuity planning for building residents. However, these evaluations cannot be based on strong-motion records alone, because earthquake observation equipment is not installed in most such buildings in Japan. In this study, we propose simple equations for estimating the stiffness degradation rate and the peak inter-story drift ratio (PIDR) by using ambient vibration records instead of strong-motion records when high-rise RC buildings are subjected to a severe earthquake. More specifically, we propose one equation that relates the square root of the stiffness degradation rate, which is the ratio of natural frequencies at the maximum response to the preliminary tremor response (elastic state), in strong-motion records with the ratio of natural frequencies identified from ambient vibrations before and after damage was suffered. We also propose an equation that relates the PIDR with the stiffness degradation rate on the basis of the stiffness-degrading bilinear restoring force characteristic derived from the strong-motion records of 13 high-rise buildings for the 1995 Hyogoken-Nanbu Earthquake (Mw 6.9) and the 2011 Tohoku-Oki Earthquake (Mw 9.0). Copyright (c) 2015 John Wiley & Sons, Ltd.