Most of housings in the Eixample district of Barcelona are unreinforced masonry buildings, which have been constructed without any seismic resistant consideration. Furthermore, they show some particular features, typical of the constructive techniques at that time, which have been identified as additional potential damage sources. In order
to evaluate the expected seismic performance of these buildings, a typical six-story unreinforced masonry building was modeled. The dynamic behavior was studied by means of a structural analysis procedure, which uses macro elements to model the masonry panels. Monte Carlo simulation has been used to take into account the uncer-
tainties in the mechanical properties of the materials. In this way, the mean seismic capacity curves of the building and their corresponding standard deviations have been obtained. The seismic demand has been considered by using response spectra proposed by the Cartographic Institute of Catalonia (ICC). The results here obtained for
the seismic performance of this type of building; make clear their high vulnerability and, therefore, it is advisable retrofitting them in order to improve their seismic behavior. Finally, a sensitive analysis shows than the methods used to evaluate the seismic performance are sensible to the uncertainties of the structural parameters.