Thermo-mechanical processed (TMP) TWIP steels with high-Mn content and different amounts of Cr, Fe-30Mn-5Al-0.5C-(x)Cr, were studied using cyclic potentiodynamic polarization (CPP), optical microscopy (OM), scanning electron microscopy (SEM), and energy dispersive X-ray spectroscopy (EDX) in a deaerated 0.1 M NaCl solution. Additionally, X-ray photoelectron spectroscopy (XPS) was used to analyse the chemical composition of the passive film generated potentiostatically on TMP specimens in the deaerated 0.1 M NaCl solution. The results indicate a beneficial effect of Cr additions on the passivity of TWIP steels. However, a high content of Cr seemed to cause a phase-segregation process reducing the corrosion resistance properties of the material. The results also indicate that TMP enhances corrosion attack.