Unreinforced masonry (URM) buiding behaive nonlinear and are vulnerable under seismic actions. URM buildings constitute one of the oldest structural systems built without considering modern seismic design criteria. Masonry is an anisotropic and heterogeneous material and difficalt for modeling. In this paper review of literature and analysis, single building, nonlinear behaviour using both nonlinear static (NSA) and incremental dynamic analisys (INDA). Relavant value of deformation obtain with both aforemention methods of analsys are compared. Seismic fragility analysis of buildings structures also analysed. In the final notes, appropriate conclusions and recommendations are formulated with reference to Eurocode 6 of the 2nd generation, which refers to masonry structures.