© 2017, Springer Science+Business Media, LLC.Deformation- and thermal-induced martensite properties were examined according to existing martensite morphology and magnetic properties for same prior austenite homogenization conditions in Fe-27%Ni-4%Mn-1%Zn alloy. Scanning electron microscope (SEM) and vibrating sample magnetometer (VSM) characterization techniques were employed for the investigation. Scanning electron microscope observations showed that while martensite formation in the austenite phase of alloy exhibited a lath morphology by thermal effect, elongated deformation-induced martensite morphology exists after deformation. The Curie temperatures were detected at about 201 K for thermal-induced martensite and at about 226 K for deformation-induced martensite from VSM measurements. The magnetic saturation values were determined as about 21 emu g−1 for thermal-induced martensite and 23 emu g−1 for deformation-induced martensite. We found that magnetic saturation increased with deformation effect. On the other hand, VSM offered the soft ferromagnetic characteristic with coersive values of 36 Oe for thermal-induced martensite and the soft ferromagnetic characteristic with 47 Oe for deformation-induced martensite. The changes in the magnetic properties resulting from the thermal and deformation affect were clearly determined. Deformation caused magnetic stabilization in Fe-27%Ni-4%Mn-1%Zn alloy.