Fiber corrosion impacts on the mechanical performance of steel fiber reinforced concrete (SFRC) have been considered minor. However, this may be true only for ordinary corrosion conditions. For severe corrosion conditions, such as stray currents, the impacts must be investigated. This study addresses the influence of corrosion at different levels, including severe corrosion, on the flexural performance of SFRC. An experimental study focused on a three-point bending test, considering as variables the corrosion level, the fiber content, and the fiber aspect ratio. It was confirmed that corrosion can shift fiber failure from pullout to rupture, and it was found that corrosion can shorten flexural performance by as much as 80%. Therefore, corrosion impacts, in certain conditions, cannot be considered minor; rather, they have to be considered significant.