Thermally induced martensite properties in Fe-29%Ni-2%Mn alloy were investigated according to martensitic transformation kinetics, morphology, magnetism of both austenite and martensite phases and also in terms of martensitic transformation start temperatures (Ms) for different austenite grain sizes of alloy. Kinetics of the transformation was found to be athermal. Also only lenticular martensite morphology was observed during investigations. On the other hand, Mössbauer spectra revealed a paramagnetic character for austenite phases and a ferromagnetic character for thermally induced martensitic phases. Determined Ms temperatures were found to be at - 128 °C for large grained samples and - 135 °C for small grained samples. © 2006 Elsevier B.V. All rights reserved.