A nanocrystalline surface layer on 316L stainless steel was fabricated by cavitation followed by low-temperature annealing. The corrosion characteristics of the nanostructured surface in 0.9 wt.% NaCl solution at 25 °C were investigated by electrochemical measurements. The nanocrystalline surface leads to a lower susceptibility to pitting corrosion and higher repassivation power as indicated by noble shift in the pitting and protection potentials, and lower corrosion current density. In addition, the pitting resistance of 316L increases with the decrease in grain size.