The article proposes a method of evaluation of residual fatigue life of metal beam of reinforced concrete superstructures of road bridges. In the calculations of residual fatigue life were implemented statistical data of endurance characteristics of steel structures that mostly fully corresponds to the given junctions by design, material, production technology and force impact. Fatigue life is determined based on the hypothesis of linear addition of fatigue damage accumulation. The critical damage amount providing the target reliability considered equal to one. Residual fatigue life of metal beams is calculated based on endurance characteristics of different groups of welded joints.For the life period assessment the motor transport load including prospective is reduced to the estimated. The reduction factor is defined based on the stress level, asymmetry factor of stress cycle and steel grade according to the conditions of equality of fatigue damage accumulation. The method allows determining of the remaining fatigue life of welded metal beams according to the transport load. Service limit and usage mode are predicted based on the structural calculations taking into account defects and damages using actual size and considering manufacturing, constructing and operational defects. Moreover, changes of strength and fatigue characteristics should be taken into account. The method of evaluation of residual fatigue life of metal beam of reinforced concrete superstructures of road bridges proposed by the auther requires clarification of te current and future load impact. The fatigue life mostly depends on the performance of superstructures maintanance and repair works.