A detailed seismic performance assessment procedure has been developed for RC frames with masonry in-fill walls. The procedure is based on member damage functions developed for the primary components: columns, beams and in-fill walls. Investigations carried out to determine the influence of a number of parameters on the damageability of components were combined with experimental data to develop component damage functions expressed in terms of member deformations. The component damage states are combined taking into account their importance to determine the story and building level damage states used to assess its performance. The procedure has been calibrated and compared with other procedures by predicting the observed performance of buildings exposed to recent earthquakes in Turkey. It was observed that the damage experienced by most of the components of these buildings was predicted satisfactorily, and that the observed building damage states were captured. It has been applied to several existing representative buildings located in Zeytinburnu to evaluate their performance under an expected future earthquake. The procedure can be used for a reliable performance assessment as well as performance-based design of RC frame structures.