In the first part of the paper, the crack growth process in rolling contact fatigue has been investigated on ring type plate specimens, in which crack growth is two dimensional and cracks are observed on the side surface of the specimens. The results have shown that cracks are initated from the contact surface in tensile mode in the direction approximately normal to the contact surface and after some short length of growth, shear mode growth occurs from the tip of the crack and it grows until the separation of the surface layer, namely flakung type failure, occurs. In the second part, mode U fatigue crack growth tests have been made by using an apparatus designed based on the concept that the subsurface fatigue crack growth in rolling contact fatigue is the mode U fatigue crack growth under the stress state where the tensile mode growth is suppressed by compression stress. The rest results have shown that the mode U fatigue crack growth occurs if the superposed compression stress is enough to suppress the tensile mode growth