The magnetic response, microstructural and texture changes occurring during cold rolling of a Fe-14Mn-0.64C-2.4Al-0.25Si medium stacking fault energy TWIP (twinning induced plasticity) steel have been studied by X-ray diffraction and magnetic techniques. The changes in the sub-grain size (Ds), probability of stacking fault formation (Psf) and microstrain in the material as cold rolling progressed were determined by using a modified version of the Williamson and Hall equation. A strong development of the crystallographic texture with increasing deformation was observed. Deformation-induced formation of a small fraction α’-martensite was observed, indicating that the steel also exhibits γ→α’-martensite transformation during cold rolling, which is discussed via the changes of the stacking-fault probability and the texture development during cold rolling. The magnetic response, microstructural and texture changes occurring during cold rolling of a Fe-14Mn-0.64C-2.4Al-0.25Si medium stacking fault energy TWIP (twinning induced plasticity) steel have been studied by X-ray diffraction and magnetic techniques. changes in the sub-grain size (Ds), probability of stacking fault formation (Psf) and microstrain in the material as cold rolling progressed were determined by using a modified version of the Williamson and Hall equation. A strong development of the crystallographic texture with increasing deformation was observed. Deformation-induced formation of a small fraction α’-martensite was observed, indicating that the steel also also exhibits γ → α’-martensite transformation during cold rolling, which is discussed via the changes of the stacking-fault probability and the texture development during cold rolling.