A nanocrystallized surface layer of around 150 µm thickness was created on AISI 304L by nano-scale surface peening. Electron back scattered diffraction (EBSD) has revealed that the upper layer of the nanocrystallized surface was formed by nanosized ferrite grains. However, bottom layer was compounded from martensite and deformed austenite. Tribocorrosion behavior of the nanocrystallized surface against alumina was investigated in a mixture of olive pomace and tap water filtrate. Nanopeened 304L was more sensitive to tribocorrosion under intermittent sliding than continuous one due to depassivation/repassivation phenomena. Mechanical and corrosion wear components were quantified. Tribocorrosion mechanism was dominated by abrasion mechanical removal of the uncovered surface. The wear resistance of AISI 304L surface was markedly improved by treatment. That improvement could be explained by the higher hardness of nanocrystallized AISI 304L.