Abstract | In this paper a robust method for simplified prediction of peak floor acceleration (PFA) demands in inelastic structural walls is established. In structural walls the plastic mechanism is usually confined to the domain straight above the foundation. It is, thus, reasonable to assume that in wall structures only the response contribution related to the fundamental mode is significantly affected by inelastic deformations. Based on this assumption, a readily developed complete-quadratic-combination (CQC) modal superposition rule for elastic median PFA demand prediction is specialized to inelastic structural walls. In this approach, only the first mode contribution on the PFA demand is affected by inelastic deformations, related to the lateral strength reduction factor identified from the outcomes of a first mode pushover analysis. Since the response contribution of the higher modes is assumed to be elastic, for these modes the relations derived for unlimited elastic structural behavior enter the specialized response spectrum method. Application on a 12-story shear wall shows the accuracy of the predicted median PFA demands derived by the proposed procedure.