The research results concerning the rate and mechanism of corrosion in aluminum alloy 6201 of the Al–Mg–Si system in a NACE solution are presented. The alloy was studied in three states: after standard treatment T6 (quenching + aging) and after the intense torsional plastic deformation (ITPD) at the temperatures of 130°C (d_av = 280 nm) and 180°C (d_av = 440 nm). It was shown that the corrosion resistance of alloy after ITPD is lower than in the case of state T6. The corrosion rate of alloy after ITPD at 130°C is higher than that at 180°C. The change in the surface roughness was analyzed.