A new post-earthquake seismic performance assessment method for structures which takes into account residual displacements is proposed. The post-earthquake residual displacements and the observable damage to the structure are considered to obtain improved estimates of the maximum deformations that took place during the earthquake. The improved estimates of the maximum deformations are expected to yield a better picture of the extent of damage to the structure. As a result, better informed decisions regarding the post-earthquake usability and repairability of the structure can be taken. Both the uncertainties associated with the structural properties and the probable errors owing to the imperfectness of the analytical models are considered in the proposed method. A trial application of the method to a real structure tested on a shaking table is presented.