Abstarct: In developing countries, usage of steel fiber reinforced cementitious composites is widely expanding in structures, due to their high mechanical performance and their flexibility. Little information exists on the corrosion characteristics of steel fiber reinforced concrete. The goal of this thesis is to investigate the behaviour of steel fibre reinforced concrete exposed to corrosive environments. Series of experiments were conducted to provide corrosion conditions for SFRC specimens. About 80 specimens were cast and tested. Three test programs were conducted: one dealt with the effect of corrosion on steel fiber reinforced mortar specimens, next considered the effects of using precorroded fiber in mortar specimens, and the other dealt with the effect of corrosion on the behaviour and the failure modes of a single fiber pull-out test. Different exposure periods, types of solutions and the temperature of environment were taken into account. The effects of corrosion were evaluated by measuring several variables: mechanical properties of the composite (in bending, compression and toughness), evaluation of corroded surface of the fibers, and the mesurments of minimum fiber diameter after exposure. All experimental results showed that, at early stages of corrosion, the mechanical properties of the composites are generally improved. It can be the result of the expansion of steel fibres due to corrosion and therefore, their better anchorage in the matrix. However, after reaching a certain degree of corrosion, the mechanical properties are decreased. In fact, the loss of steel in fibres due to the corrosion of this stage causes this deterioration in the mechanical properties. It was also observed that for a certain level of exposure or degree of corrosion, the decrease in the toughness of steel fibre reinforced concrete is much more than that in its strength.