Influence of irreversibility (magnetoplasticity) on inverse magnetocaloric effect and magnetoresistance of the (Ni,Cu)(50)Mn36Sn14 alloys has been investigated by magnetization and resistivity measurements. X-ray powder diffraction patterns indicate that all alloys crystallize in L2(1) cubic structure at room temperature. The substitution of Cu for Ni leads to decreasing on the martensitic transition temperature and increasing on the Curie temperature. The magnetic field dependence of magnetization measurements is performed with continuous heating and noncontinuous heating methods to find the influence of irreversibility on magnetocaloric effect. It is observed that the magnetic entropy change depends strongly on magnetization measurement methods. The resistivity measurements show that the (Ni,Cu)(50)Mn36Sn14 alloys have the one-way magnetostructural transition. Magnetoresistance about -46% is observed at magnetostructural transition temperatures. (c) 2010 Elsevier B.V. All rights reserved.