Fragility curves are predictive models estimating the damage caused by earthquakes of variable intensity towards a given building typology. This work aimed to calculate analytical fragility curves for an existing masonry building type widely spread in the Casentino area, within the Arezzo district, dating back to the 1960s-1970s. Generally, these buildings consist of 3 or 4 levels and they are provided with floor slabs effectively connected to the walls through RC ties. The studied building set was obtained partly from known geometries of actual buildings and partly from a statistical study of existing buildings. The geometric and structural parameters variance was evaluated based on actual features of the buildings within the investigated area. A series of nonlinear FME (Frame by Macro Element) simulations were carried out to calibrate the fragility curves and highlight the most influencing parameters: the material type, the opening percentage at the building base floor and the structure number of floors. Finally, a database of fragility curves was carried out concerning these most significant parameters on the investigated building type seismic response.