In vitro corrosion tests have not evaluated the role of cells on the corrosion of implant quality 316L stainless steel. A new cell-culture corrosion cell was used to simulate the clinical condition of cells attached to and growing on the alloy to evaluate the effects of cells on alloy corrosion and the effect of corrosion products on cells. The corrosion potential, charge transfer, and surface composition of the alloy were measured in the presence and absence of macrophage cells (RAW 264.7) or cells stimulated to release NO over 72 hours. Whereas there was no statistical difference in the corrosion of 316L stainless steel in the presence of macrophage cells as compared to culture media alone, there was a trend for higher corrosion to occur in the presence of the cells. Corrosion was further reduced when cells were stimulated to release NO which may have oxidized the implant and contributed to an enhancement of its surface oxide. These data suggest that cells may alter alloy surface oxides and affect alloy corrosion.