Abstract A large number of parameters affect martensite formation in steel, such as composition, applied stress, plastic strain and temperature. Low cycle fatigue tests on 316L austenitic stainless steel have been carried outwith different strain amplitudesat room temperature and cryogenic temperatures. The influences of deformation and temperature have been investigatedby carrying out in-situ and ex-situ neutron diffraction measurements in the ENGIN-X diffractometer at ISIS (UK) to analyze the volume fraction and strain in the martensite phase. Increasing plastic deformation and decreasing temperature were shown to promote martensite transformation and increase the hardness of the material. The influence of the appearance of martensite due to deformation and temperature will be discussed.