Abstract: This paper presents a study of the metamagnetostructural transition of the martensitic type in the Ni46Mn41In13 alloy with magnetic shape memory and inverse magnetocaloric effect. Differential scanning calorimetry was used to determine the characteristic temperatures of the direct transformation (start at M_s = 253 K, finish at M_f = 164 K) and the reverse transformation (A_s = 203 K and A_f = 236 K, respectively). The characteristic features of the transformation, that is, a decrease in the temperature of the onset of the direct transformation and the presence of a residual austenite phase, and premartensite states, were studied using transmission electron microscopy. The estimated thickness of the material at which the martensitic transformation is suppressed is 50 nm.