Kinetic, morphological, crystallographical, magnetic and thermal characteristics of thermally induced martensite in Fe-25%Ni-15%Co-5%Mo alloy have been investigated by scanning electron microscope (SEM), transmission electron microscope (TEM), Mössbauer spectrometer, and differential scanning calorimeter (DSC). Kinetics of the transformation was found to be athermal. Also only lenticular martensite morphology was observed during microscope observations. In addition, martensite start temperature (Ms) was determined as -63 °C from differential scanning calorimeter. On the other hand, Mössbauer spectra revealed a paramagnetic character for the austenite phase and a ferromagnetic character for thermally induced martensite phase. © 2009 Elsevier Ltd. All rights reserved.