The deformation induced martensitic transformations in a Fe-17Mn-1.9Al-0.1C steel are investigated by X-ray diffraction and magnetic measurements. Martensites alpha' and epsilon are formed at the same time during cold deformation of the steel. The starting (A(s)) and final (A(f)) temperatures of the reversion of martensite alpha' during continuous heating are 390degreesC and 540degreesC. The martensite epsilon seems to be reverted in the 300degreesC-450degreesC range. These results are discussed and compared with those previously obtained in conventional stainless steels.