Intensive seismic events show the particular impact of these actions in the destruction of the built heritage. The Mudejar architecture has been analysed from the standpoint of the structural behaviour under seismic actions, trying to verify the response of these buildings if today they needed to face an earthquake. Dynamic analysis in situ of the structural rigidity is proposed for the seismic design, protection and rehabilitation of existing structures. This method makes possible the knowledge of the building, contributing to the restoration works through the proposal of specific constructive solutions according to the particularities of each building.