This work deals with a specific masonry building and its behavior after the 2009 Abruzzo earthquake. In this study are established a set of different objectives directed to the understanding of the structural behaviour of the San Marco church in L’Aquila under the seismic actions, taking into account its initial conditions, such as the past structural interventions or the quality of the existing material. The knowledge attained form this type of studies is a matter of great interest and importance, in particular for the entities that control the preservation of the built heritage, because it helps to prevents future errors and allows the definition of more efficient intervention strategies, so important for the preservation of this type of buildings in the case of another seismic event. As so, the objectives purposed for this study are the following: • Present the result of a brief historical research, paying special attention to the transformation/structural interventions performed to the church throughout time. Describe in a more detailed way the existent structural interventions and assess its efficiency discussing how they influenced the structural behaviour of the church in particular the damage mechanisms. • General and structural description of the San Marco church. • Assess the present state of damage, through the elaboration intuitive damage maps. • Analyze the activated mechanism on the church and its level of activation, according to the abacus present on the 1st level form (“Scheda per il rilievo del danno ai beni culturali – Chiese”). • Perform the analysis of the collapse mechanisms of chosen structural elements using c-Sisma program. • Correlate the present overall damage state of the church with the pre-existent interventions, the material quality and the activated damage mechanisms.