We present results on the magnetic field-induced martensitic phase transformation in Ni 2 MnGa. The experiments were carried out in a wide temperature range from 10 to 300 K and in magnetic fields up to 5 T. Two successive anomalies in the temperature dependence of main (220) peak width, corresponding to martensitic transition temperature (T m ) and premartensitic transition temperature (T p ), respectively, are detected. It is found that T m increases and T p decreases with applying magnetic fields up to 2 T, and then the transition temperatures do not change in fields up to 5 T.