The effectiveness of Fibre Reinforced Cementitious Mortar (FRCM) as strengthening technique of masonry structures under seismic actions has been widely investigated by means of diagonal compression tests in the last decade. The results showed that the effectiveness of FCRM solution, based on the use of FRP grid embedded in mortar matrix, to increase the masonry walls shear capacity strongly depends on the axial stiffness of mesh reinforcement and on the mechanical properties of the matrix. The paper presents preliminary experimental results of tests carried out on specimens strengthened with a new strengthening solution based on the use of Fibre Reinforced Mortar (FRM) without the use of FRP grid. In particular, the strengthening system consists of an innovative high performance and high ductility mortar made by a mix of fibres spread in lime-based powder. The experimental program aims at investigating the soundness of such technique to increase the shear capacity of different masonry panels. In particular, the system was applied over limestone masonry walls with irregular texture, typical of existing buildings in Central Italy, and old-type clay brick masonry panels with regular texture, typical of existing buildings in the Northern Italy .