An experimental program conducted at Enel-Hydro ISMES showed that externally applied fibre reinforced polymers (FRPs) are effective in increasing the load-carrying capacity of plain ancient masonry walls that are subjected to in-plane shear loads. Twenty walls with height of 1,6 m were used to conduct 20 tests. Both plain and reinforced walls were tested . The following experimental parameters were investigated: (1) type of fibre reinforcement; (2) amount of fibre reinforcement; (3) layout of fibre reinforcement. The modelling activity has been oriented towards establishing a numerical approach , which is applicable to vulnerability assessment of real large scale structures, in support to retrofitting design.