Brush electroplating causes a marked reduction in the fatigue strength of the base steel. For the medium carbon steel reported in this paper, the fatigue limit is reduced 28.6% by nickel brush electroplating. A large number of short cracks are found in the nickel coating, and the coating usually suffers a high value of internal tensile stress. These are two reasons that cause the loss of fatigue strength. Shot peening has been used to minimize the loss of fatigue strength caused by brush electroplating.