Ferromagnetic Ni-25at%Mn-23at.%Ga shape memory (SM) alloy was fabricated compositionally uniformly in vacuum using an electric furnace, and its polycrystalline specimens were deformed monotonically in compression and cyclically in compression-unloading-heating-cooling mode at room temperature. Polycrystals deformed in compression at various temperatures showed perfect SM effects and superelastic behavior, and using Clausius-Clapayron relationship, the martensite and its reverse transformation temperatures were determined. Polycrystals failed within several cycles when deformed cyclically at above M-f point, while no failure occurred up to 100 cycles at strain amplitudes between 1.1 and 4.4% when deformed cyclically at near M, point, although intergranular fracture occurred. The result suggests the Ni2MnGa alloy should be intrinsically ductile.