The tribo-electrochemical behavior of two new martensitic stainless steels in a 3% NaCl solution has been investigated. Different electrochemical and surface analysis techniques (Scanning Electron Microscopy, Focused Ion Beam) were discussed to analyze the influence of the effect of the electrochemical conditions on friction and wear, and to elucidate involved wear mechanisms (plastic deformation, plastic shakedown and low-cycle fatigue). The selected stainless steels degrade through a delamination type of wear mechanism. The effects of the applied potential on wear are related to the formation of a passive film which alters the mechanical behavior of the surface and subsurface of the materials to promote wear. A coefficient of friction below 0.6 promotes nanowear, and a transition was observed when the coefficient of friction exceeded that value.